The main pivot will be the most crucial as the majority of the torsional forces will be transmitted through it, my plan is to overbuild the area slightly so to be sure it holds up.
Here is a rough sketch of how I intend to do the main pivot - I plan on using two bearings housed in a steel insert that will be bonded into the frame, I will then have a 12mm axle that the swingarm will be attached to, which should hopefully be rigid enough! The blue signifies where I will put a nylon washer on each side to allow for tolerances to be slightly off without creating play.
These are the bearings I hope to use - the flange should allow me to locate the bearings exactly where I want them without any complicated retention methods.
For the top linkages I intend to use mainly nylon bushes mainly for the sake of simplicity and saving weight, but also they are significantly cheaper to get hold of (about 50p each). The drawing below shows one half of the shock/linkage/chainstay joint, the red writing signifies the rough widths of each part - so 34mm for each side with a total width of 68mm, which I feel is the upper limit before you will start catching your knees in the case of an accident. I will use a standard shock mount from with a 10mm center hole to allow me to run a single shaft through the whole assembly.
For the more simple linkages I will just use a simple nylon bushing, that I will put a 10mm steel bar through so should rotate nicely, and be really simple and cheap to maintain.
Any questions feel free to message me or comment on here and I will try to answer!