I trim some of the fan leaves that prevent light from getting down to the lower bud sites, but I've never noticed my plant slowing down in growth. The lower bud sites are getting bigger now too as result of trimming those fan leaves I assume.

I'm also a big fan of fimming as it produces more node sites and makes your plant "denser" giving you more bud sites. I'll usually do it to 4 bud sites doing it every other.....