I got a Sealey spray attachment gun, which you do need a compressor for. The 1 litre cans screw straight on, and it comes with a spray end, and a 500mm tube that has a 360 spray head to get into small places.
The good news though is, you can by a 1litre can for the same price as a 350/400ml spray can, and the gun is not that expensive, so once you go over 3 or 4 cans, it basically pays for it's self.
When I had gone through about 6 x 1litre cans, and realised just how much waxoil you use to do inside the chassis, and underneath, I bought the 5 litre can, which works out even cheaper still, but you do need to have kept some of the empty 1 litre cans to decant it into so you can attach it to the spray gun.
Clean up is pretty easy,
I got a 1litre bottle of white sprite, and a couple of cleaned out 1litre waxoil cans. I then put about a 1/4 litre of dirty white spirit in one can (stuff I used for clean up before, and spray it through the gun and tube if I have used it, into the other can. Then when the worst is out, put a bit of clean white sprit in the can and spray that through into the dirty stuff. Then put them away for the next time.
Eventually the "Dirty" white spirit has so much waxoil in it, you can actually use that with a brush to paint onto areas you want it to run into seams.
A tip, put the cans in a bucket of very hot water for a while then shake them up and return them a few times, before you use them. It thins the waxoil, making it a lot easier to shake up, and a lot easier to spray, but do remember to reduce the spray pressure to a lot lower than they recommend as you can empty a hot can in about 30 seconds at their pressure... I think I ended up down at about 30 or 40PSI, where as I think they talk about 70(ish).
Edited to add, do an ebay search for "schutz spray gun"
