If yr looking for 5 shot, than its easy; LP10, morini and AP40 are all singleshot..
Besides that, we cant give you good advise what pistol to choose. Matchguns are SO personal! Feel the pistol, aim it, and choose what suits you best.
I can give you additional info though:
The 162: the old one's have a non-detach cilinder. (the E), new one's have a detach cilinder (EI). BUT none of the E's are adjustable for grip cant! The M ís.
The morini grips are great. Imo far better than the thin steyr one's. But as said, its personal! Quite small sights though.
AP40: now made by walther/umarex. Hammerli doesnt exist anymore, so spares may become an issue. There were 2 AP40s made, the old 1 with alu barrel, which is very light up front, and the newer one's with steel barrel. I like their large sights and thick grip.
Filling should be directly on the bottle; using a fillingset will empty the cilinder when you bleed air..
If I were you, I'd go to a match shop and feel as much pistols as you can. Dont fear less common pistols; they're just as accurate, and often based on common brands. (gehman, etc). There are lots of brands: Walther LP (VERY nice 300 bar system in the LP300, great 3D grips), the new LP400 is similar to the LP10. The Steyr, morini, Gehman, Tesro, Sam, Pardini, Benelli, FWB, etc.