Bicycle Mechanics - First carbon fiber frame build. Couple Qs.

I have the torque wrenches and the fork steerer is already cut to measure.

Mainly I'm wondering where to use grease, and where to use carbon paste. I'll be using alloy handlebars and stem, not sure about seatpost (carbon or alloy).

Is it mainly carbon-carbon -> paste
alloy-alloy -> grease (bottom bracket, etc. not handlebar-stem)

How about the carbon steerer? Carbon paste on the seatpost regardless of material?

Any other tips/caveats highly appreciated!

I use carbon assembly paste on all carbon parts that you'd apply grease to if it were an alloy.
I use it were you need to torque things so you can do it to specs and not worry about any slippage this includes FD clamp to seat post if you have one.
If carbon is involved no grease for sure!

Yep, you got it pretty nailed down.

Carbon -> carbon , paste.

Alloy -> alloy, grease (maybe anti-seize for pedals, but grease is what I've always used)

I use an alloy seatpost in a carbon frame, and I use paste for that always.

Anything on carbon, paste in my opinion, carbon steerer especially. I don't know if you have to use anything on the steerer FWIW.

That's it pretty much.

Alright, thanks for the feedback guys!

I have two bikes with alloy stems and carbon steerers and have always assembled them dry, no grease and no paste. Neither has ever slipped even when torqued at the low end of the recommended spec. However, stem/steerer interfaces see little torque or load. For a carbon seatpost in any material frame and for carbon bars in any stem, paste for sure.

There was a few fork failures awhile ago that were blamed on carbon paste being used on the steerer/fork interface.

No idea if it's a real issue but I have never used carbon paste on the steerer and even with minimum torque have never seen a stem slip.