Update: I installed the stock BB with no inner spacer, just to have more chances to remove it later; I plan to order thread in BB, ZTTO or token; if aliexpress is involved is going to take a while.
Chainline: I installed the 52 mm Xt crank, as said before the clearance with the lower frame is minimal, I measured it is 0.8 mm; I think it could stay like this, moving the crank out will harm the chainline: like this is aligned on the 4th gear from the smallest. I think 0.8 mm flex on the chainring will not happen.
Geometry: I put on fork and wheels to work on geometry: my handlebar hasn't much rise, maybe just 20-30 mm, but I feel like adding a lot of spacers under the handlebar, up to 5 cm: is it normal?
How much higher do you need to raise your seat to pedal efficiently? I personally don't like the way a bunch of spacers under the stem looks, but I also don't feel like it needs to be that high. But better to cut the steerer long and use spacers until you can ride it and see what feels best. You can always move the spacers around to see what feels right and trim it later.
I'm waiting for a 40mm stem and have a 60mm on currently and will probably go with 1x 10mm spacer under and 1x over. As it is, the stack on this bike is 48mm more than my current bike which is quite a bit higher and about like adding 5cm of spacers to it so I'm a bit surprisedthis frame feels like that much is needed, but everyone is different. Also, the reach is about 40mm more than my current bike but the distance from saddle to bar is almost exactly the same on both and with the 40mm stem will be shorter and quite a bit higher so will be more upright and comfortable. But with this newer geometry, I'm expecting to have to play around with the cockpit to see what feels good and puts enough weight over the front to get good traction and works best.
I was worried about chainline since I ordered a 7120 crank with 55mm chainline. But that is also what Shimano considers a boost crankset and is recommended for use with boost rear hub spacing so it can't be too bad. Also, I went with a ZTTO thread together BB which must be wider than a normal PF92 BB because I was only able to use 1 spacer which I put on the non drive side. If a 7100 crank has an axle that is 6mm shorter, I'm not sure it will work with the ZTTO BB? Just something to consider for anyone thinking about that combo. With that setup there is about a 1mm gap between the chainring bolt and frame, and about 5mm between tips of 32T chainring and frame. Don't think I would want it any less, and it might not be ideal but I think that crank is the only way it would all work with the setup I went with.
Has anyone come up with a fender or some type of protection for the bottom linkage and back of the shock? It's all right in the path of the tire and I can't imagine it all holding up that well to very many days of mud or rain...