how do i go about trimming the lower leaves? here is a picture of where i started to trim some of them on one of my plants but i didn't want to do too much or go too far w/o knowing what is good practice. You can see in the front plant that i trimmed some of the leaves on the outer-most bine just about a foot up. Should i do that for all of them, and how high should i go? for refernce the shortest of the 3 is now at about 12 feet off the ground with about 6 feet left to go