900 big bore parts? E85? what cams? Your setup?

So iam starting to build a 975 big bore. I got a cylinder works big bore "I know" it was free. Using offset Carrillo rods, cams, ported head, bored throttle body’s, valves springs ect. I have a intake and alba slip on. Clutching to come. It’s mostly going to be used on mx tracks and gncc. Now to see what other people are doing for the best cam setup fuel. E85? And anything else?
1 what cams with this setup alba stage 2 or 3? No crazy wot runs like dessert.

2 anyone see any advantage of running e85 in a n/a 10.5:1 motor that outweighs the cost to upgrade the fuel system.

3 anyone milling the heads or cylinder to boost the compression without having to buy new pistons if so do you have timing chain slack Issues?