Ideally 50/37 or 48/36, I was looking at carbon ti outer and sram inner some doubt if they marry. Or force ones.
My thinking being that anything less than 48 won’t improve top end speed with slicks much.
43x10 would get you to 56.6kmh Vs 59.8kmh on 50x11
(Assuming 100rpm and 38c tyres)
So very similar to a traditional road compact set up with 11t smallest cog.
Depends on the frame and the chainstay clearance.
If you are running single ring, you may find that the regular dub is limited to a 38 or 40t. Wide will let you run way more.
In terms of double, you just get more clearance for the front mech etc I believe
I guess it all depends what chainring/s you have planned