The gear limit is by rollout, so you can go to a 50x34 compact crank. Also, I have never seen someone cranking down a VT hill that is faster than a nose off the front wheel, balls-to-the-wall tuck.

I remember when age 15 and under the limit was 52-15. Which at the time was amazing how they stipulated that since it took me forever to find a shop who could remove cogs off a Shimano 600 6-speed freewheel and reconfigure with a 15t cog. I still have that freewheel somewhere. Then of course not once did anyones bike ever get checked. I was one of the very few stupid fools who actually complied with that rule, well actually I never found any other rider who had complied.