Removing the ground glass to fit the roll film can be a pain at times, but if you're using the horseman as a view camera, it's not really a big deal, just make sure you have a safe place to put it while it's off the camera.
as many medium format users I guess, the motivation for me comes from the frustration of lacking movements when shooting architecture or in fact many things in cramped urban settings, which means basically most old cores of any european town.
Typically I walk with a shoulder bag with, these days, a Bronica S2, couple backs, couple lenses, often a light carbon tripod. The idea is to carry instead a Horseman when I suspect I will have some architecture to shoot sometime in the day, but not only. I thing bulk and weight will be similar, but i will just need more time for the frames requiring movement and that's what I'll try to optimize. So I will just have to see how it goes with and without Grafmatic.
anyway, I looked online, and only ebay had six listings, all fixed price around 100usd and one low starting auction, for these 2x3 Grafmatic. The 4x5 are many.
It was a while I didn't buy by auction. There were only two bids at 30 or 40 usd in that short-term auction duration. I did an ambush buy: jumped in the last 40s before ending with a 90usd bid, after 20s the 90 was outbid so I injected a 120, the other guy increased but not enough, I had a 150 ready to go, but didn't need, won at 107usd. Add 30usd for shipment and 40usd for norwegian vat, haha, so 177usd. But it is 2x Grafmatic 23 and one 2-sheets holder:
and still have not bought the camera+back+lenses combo... but at least have secured these Grafmatic 23. They will arrive after the camera anyway, as stuff from USA seem to need three to four weeks to arrive, but from Japan one week ...