Light-weight tripod for Ebony RSW45 walking Kit

I am putting together a light weight 5x4 kit that I hope to be able to carry all day without developing back and neck problems. So far I have trimmed my outfit down to an Ebony RSW45 with Fujinon 150mm f5.6 and a 90mm f6.8 Angulon. Add to this 6 to 8 Fidelity cut film holders. The major problem is the tripod. My current model is a Manfrotto 055 pro with a Gitzo ball and socket head. While this combination has served me well, at 3.1 kilos it is too heavy to carry all day. As the camera with the Fuji lens is only 1.8 kilos I am looking at carbon fibre tripods that will be rigid enough for my purposes but light enough to carry all day strapped to the side of a rucksack. I would hope to be able to keep the ball and socket head (Gitzo 1276M) as it is nice and small and works well for me. I know that Manfrotto and Gitzo are compatible with this head. Does anyone know of any other brands compatible with Gitzo heads?
Also what is the minimum max load I can get away with in the tripod specification? I was thinking perhaps 5kg but can I go to 3kg and still have something worthwhile using?
I'm not the first person to ask this kind of question I know, but I would value comments from anyone who has tried to devise a real bare bones kit like this.
Thanks, Steve

Most tripods mainly for still photography with interchangeable heads will accept any head with a 3/8"-16 screw fitting. I've settled on one of the carbon fiber Feisol tripods for my lightweight option. I would only suggest avoiding one with a telescoping column, which mine had, and which I've modified by removing the telescoping section and re-attaching the end cap with epoxy to the shortened column. Aside from shaving a few ounces off the total weight, the solid column is sturdier and not prone to unintended panning at the telescoping joint (which could happen even without the telescoping section extended).

This is the one that I use--

http://reallybigcameras.com/Feisol/Traveler_Class.htm

It's very light and folds compactly, and does fine in most situations (no super long extensions or high magnification macros) with a camera up to 4x5", or even my ultralight 8x10" Gowland with a lighter weight wide-to-normal lens and not too much extension. Depending on how big the camera is, I either use the small Linhof Universal Ballhead I or the Acratech Ballhead (which is larger) with it. The larger head won't fold inside the tripod with the legs reversed, so I either transport it without the legs reversed or carry it in the tripod bag with the head detached.

If you don't need it to be the minimum folding length (I wanted it to fit in my suitcase and to directly replace my compact Linhof Report tripod), you could get a larger model without the 2-section telescoping column.

There is no way of going light weight with 5x4 - I'm using a Wista field with a Fujinon 135 & Rodenstock 180, and my average load is rarely less than 10Kg. My tripod is a Giottos MTL8361B (1.8Kg) and a Manfrotto 804RC2 (700g) - The head is probably a bit too light, but it does the job.

Thanks David; thats just the sort of experience I am looking for. I know that travelling on foot for 6 or 7 hours with a large format outfit will never be a light weight option. I just want the lightest weight option.

I have and use Tachihara 4x5 which is indeed very light. As it was mentioned - 4x5" setup is never truly lightweight, but light tripod helps. I got myself few years back a Feisol CT-3442 (s.c. Tournament) which weights 1kg and a Photo Clam Ball head (either the 33 or 36 size - not sure) which weights about 350g (both from Kerry Thalmann - reallybigcameras.com). This setup is sturdy enough to carry the Tachi (even with 400/8 tele-lens, where the camera limits the stability), however one has to be careful as there is some top-heaviness there. I have not found a way to get the tripod much lighter than that. The tripod is rated for up to 10kg, the head even more. Both work well too.

You could alwas lose the head and just use the tripod legs for leveling, you may need a 3/8 to 1/4 adaptor. This way you save 500-700grams of head. I personal use a Velbron 630 CF and Arcatech ballhead - 2kg all up.

David A. Goldfarb;1336519: "I've settled on one of the carbon fiber Feisol tripods for my lightweight option. I would only suggest avoiding one with a telescoping column, which mine had, and which I've modified by removing the telescoping section and re-attaching the end cap with epoxy to the shortened column. Aside from shaving a few ounces off the total weight, the solid column is sturdier and not prone to unintended panning at the telescoping joint (which could happen even without the telescoping section extended).
If you don't need it to be the minimum folding length (I wanted it to fit in my suitcase and to directly replace my compact Linhof Report tripod), you could get a larger model without the 2-section telescoping column."

I finally decided on the CT3442 based on your above observations David and searching on reviews elsewhere which are generally very positive. This has no rising centre column but the max height is 142cm which is better for me as I am 6 feet plus in height.By the time I have added the B&S head and the camera, the GG should be near enough eye level. Weight is 1.05 kilos, just slightly heavier than the Traveller version and the folded length is 5cm more. I think I will be able to live with this.
Feisol UK prices are a good bit higher than those quoted in the States but I hope to be able to sell the Manfrotto to offset some of the cost. Hopefully this will be a purchase for the long term so spending the extra will be worthwhile.

Comfort has more to do with the pack you choose than the LF gear itself. A lot of wt can be spared by using bubble wrapping etc instead of heavy foam rubber. The Ebony is very light. Carbon fiber tripods are also a luxury. I use both Gitzo and Feisol for long trips. Don't get scared about all this wt
nonsense. It will be barely more than a SLR setup. Just practice with the load regularly and get in shape. 4X5 is ALWAYS lightweight if you're accustomed to 8X10, and I'm over 60! But I utterly detest ballheads for view camera work. Their the weak link as far as stability is concerned. I don't generally use any tripod head at all. Center columns are also a liability.