Welcome to the forum. There is a LOT of information out there, get to know how to use the search and advanced search feature. Chances are really good your question, whatever it might be, has been asked before.
Something like the squeezer is a personal choice issue and you will get a lot answers. (I built my slow build with a manual squeezer from Averys.)
In place of a costly squeezer, I would rather have a 2x AND 3x rivet gun. You can do it all with the 3x gun but having both would be really nice. Use the 2x gun when riveting two thin pieces of aluminum together, say a skin and a rib. The 3x would be good for riveting to thick structures, such as your longerons.