My frame has a 30.7mm seat post clamp, looking to get a Salsa flip lock seat post clamp but the closet size is a 30.6mm, does the 0.1mm matter?

i doubt it

i run a 27.2 seatpost in a 27.o frame and its fine

No

Inbreds, for example, need a 29.8mm seat calmp but 30.0mm does fine

I agree with Kimbers but it may depend a little on the *exact* outer diameter of your seat tube. If you can get a vernier caliper it would be useful to crosscheck

OTOH a 27.0 seatpost in a 27.2 frame won't go (at least didn't in my case) it just drops down. A beercan shim works nicely in that case, but I don't think it will help in your case

worst case I suppose you'll scrape the paint of your frame at the clamp….

Thanks, for the replies, just used my Aldi vernier and the measurements are 30.3mm to 31.1mm and it looks as if the paint is a little thicker in parts, so given your comments going to order the 30.6mm

Cheers guys