Re: snap ring pliers
You can buy a set of 16" locking snap ring pliers on ebay or amazon for 40 bucks shipped. Actually 2 sets, internal and external, with about 5 sets of extra tips. I just bought a set and they are the right size for the lower unit.
Only drawback is they are made in China and they aren't the best quality, I had to use a screwdriver to coax them out. 16" US pliers are about 80 bucks at my local tool store, if I were to do it again I'd probably buy the good ones.
16" is the right size for locking style, long enough so the locking mechanism stays outside the prop housing.