Thanks, Adrian. To add pictures you need to upload them either to an image hosting site (a lot of people seem to use Photobucket) or to your own web-space which most/all ISPs provide for their customers, which is what I do. For the latter you need to use an FTP program for upload. Once the image is uploaded you write your forum post and click on the 'Insert image' button at the top (it's the one with a picture of a tiny tree!) and then insert the web-address of the picture in the dialogue box. When you've done it once it's easy, but if the learning curve looks a bit too steep I'll PM you my email address so you could send a picture as an attachment!
At the moment I'm deciding what the diameter of the pins should be; I think it will want to be just about as big as the semi-circular end on the short leg of the L-shaped slot (about .098"). steven_e007's Ranger looks that way, but a picture of an 820 would be extremely helpful as confirmation. I'm pretty certain it would be impossible to measure the diameter accurately on an assembled camera. I've got the lens-board erected at the moment with a wire through the holes, so I can see how it works, and I can see the diameter isn't critical in itself for the accurate alignment of the lens board, as I thought at first, but will affect how rigid it is.
By the way, my idea of a larger diameter shoulder to give better support where the pin fits to the strut wouldn't work due to clearance problems. Also, the lens/shutter unit came off easily once I made a suitable tool. The retaining ring has 4 slots in its perimeter and the bellows (at full extension) allow you to access two at a time, so you have to unscrew it by 1/4 turns.
Steve.