I just did the same thing to mine last night in between MMA fights... I have some lower branches that I don't want to get shaded out and the tops were getting too dense to guarantee that this wouldn't happen. Of course, mine are way smaller than yours are, but I want to keep everything growing in lockstep.
One of them required repotting (minor disaster on my part) and after only being in the pot for about 3.5 months, I was amazed how many new roots had developed. By the looks of the new growth that I'm seeing, these will need trimming 3 or 4 times a year (depending if they go into dormancy or not)... do you see the same pattern c54fun?