The spindles are either GXP or BB30/BBright (long enough to fit most BBs)
Arms are removable, and largely have the 8 bolt pattern, unless the spider is older and it has the Sram 3 bolt pattern (or you have the Specialized cranks)
If you don’t go for the DFour and Shimano rings, spiders are either standard 5 bolt, or 5 bolt sram hidden ring.
I have BSA30 on the Rotors now and it doesn't leave a lot of room in the shell for Di2. I can't tell any difference between 30mm and 24mm spindles so that's not an issue. So long as GXP bearings don't fail more often than the shitty BSA30 bearings.
The spindles are either GXP or BB30/BBright (long enough to fit most BBs)
Arms are removable, and largely have the 8 bolt pattern, unless the spider is older and it has the Sram 3 bolt pattern (or you have the Specialized cranks)
If you don’t go for the DFour and Shimano rings, spiders are either standard 5 bolt, or 5 bolt sram hidden ring.