When playing do you familiarize yourself with the actual description of Talents, or just go off of the blurb in the Spec Trees? What about in play, are the full descriptions referenced much at your table?

Typically go off Tree-blurbs but there are some, especially in Force Powers, where we've looked up enough times that we are familiar with the full descriptions and how it is supposed to work. As a GM, I try to read the full descriptions of any talents my player has when we first start so I have a decent idea of how it works and then I just rely on the blurbs - which, I admit, does allow my players to get away with some things they wouldn't if I was a little more alert.

We try not to interrupt play too much on clarifications unless it is at a critical plot point and could make a difference

Read the full text then use the tree as a reminder. Which I believe is the design intent as sometimes there is just not enough room to fit everything in the tree.

I only use the trees to see what can be bought. I pretty much only use the full descriptions for the effects.

When entering the talent info for my copy of OggDude's generator, I compare the two (talent tree text and full text), and generally wind up using a condensed version of the full text of the talent to try and cover any ambiguities as best as possible. Some of the full text descriptions are overly verbose for terms of play, so it's pretty easy to trim a number of them down to be less verbally unwieldy and still provide the correct info for what the talent dues.

For the two-page character sheets I put together for con games and one-shots, I generally go with the abbreviated text of talent tree, adding minor details on an as-needed, case-by-case basis. After all, these are generally "one and done" characters so I'm not stressed about getting every little element of the rules for those talents in writing. And if need be for those cases, I just avoid the overly complex talents outright.