If you have at least the minimum recommended twist for a bullet, 10 or 11, your 10 twist should be fine.
There's always a borderline situation someone can dream up where it won't work, but unless you're shooting at -40* at sea level or 120* on top of Mt Everest you'll be fine.
There's nothing wrong with a 10 at all so long as you match the bullets, like you're doing. I'd really prefer an 8 or 9 twist in a 300 PRC, but I prefer heavier bullets and monos that require faster twists. I put 8s on for my 30 SMs (300 PRC Improved).
You're almost on track there about lighter bullets not needing as fast of twist. A
shorter bullet doesn't need as much twist - in general that translates to lighter, but depending on the ogive radius there can be a heavier/shorter bullets.
For example the 220 SMK and 240 SMK are bother shorter yet heavier than the Berger 215 Hybrid and all three can run in 10 twists, but the 230 SMK is longer than all three of those and requires an 8 twist. Unless you really want to get into caliber of ogive and bullet design to know why it all matters, just double check the manufacturer recommended twist and make sure they label it as being good with 10 or 11 and you're fine.