Gary,
I'll try to give you a quick overview of squeezers. The most common pneumatic squeezer in use these days is a variation or clone of the Chicago Pneumatic 214 "C" type squeezer. I assume that this is what you have. There are various yokes available for this squeezer that you can use depending on how you have to reach the rivet. The most common yoke is a 2" to 3" standard yoke into which a rivet or dimple die is inserted. This die mates with the die in the squeezers plunger to squeeze the rivet or dimple the material. This yoke can be used most of the time but cannot get into tight spaces due to the length of the die. A no hole yoke does not have a die hole in it, but rather has a flat surface against which you squeeze the rivet. This tip can get into a much tighter location, but cannot be used for dimpling. This yoke is very useful for squeezing the last rivets in places such as the corners of empennage ribs. Another useful yoke is the longeron yoke which gives you the capability of squeeezing a rivet over an obstruction like a flange. I have a 2" no hole yoke, a 3" standard yoke and a longeron yoke. This seems to handle most of the rivets I've run into.
Depending on the hand squeezer you get, yokes may be interchangable with your pneumatic squeezer. The Avery hand squeezer can use the same yoke as the standard 214 clone. I have both a pneumatic and Avery hand squeezer, but never use the hand squeezer. I would wait to purchase the hand squeezer until you decide if you really need it.
If you don't have them already, I would get an adjustable set holder and quick change yoke pins for your squeezer. The pins make changing yokes very quick and the adjustable set holder make adjusting the squeezer for the right rivet length much easier. Avery has these as well.
I hope this helps. Let me know if you need more info.
Good luck on your project, you are in for a great time.