I just burnt the tunes to disk from iTunes after sending them there from GB.
I did not use a limiter of any sort. The only thing I did on the master track was fade in and out. I have no idea about master track strategies. (another topic for GB 303!!)
I have thought about jumping up to logic, but the cost is prohibitive at this stage. Also, to tell you the truth, I have looked into Logic, Ableton Live and Reaper and couldn't get my head around not only the programs, but the basic approach to work flow and comprehending the start to finish pathway. I currently have both Logic Express 8 and Ableton Live, and struggled with both to understand the big picture. I have MPV tuts for both. They are great for explaining the individual parts and what they do, but not the big picture, or specific scenario's like, "Here is how to make a 10 track CD for your friends", or "Want to play a live gig? Here some idea's". I just gelled with GarageBand and I was not only able to work my way through recording a tune, but actually remember what I did last time without having to read through the manual again!!!
The best example I can relate this to is sailing. You can have a basic yacht with half a dozen ropes to pull, 2 sails and a compass, or a tricked out beast with 50 ropes to tweak, electronics galore, redundant systems, a complete backup sail wardrobe for any wind range from 5kn to 40kn and an expresso machine. Both will get you from a to b. Definitely the 1st boat is limited, but you have to build a foundation somewhere.
I just think GB and project fundamentals could be better utilized and explained as a stepping stone to Logic than they currently are. (Maybe I'm just a dunce ;)