When I worked at Cimarron, I'd get a lot of calls from guys just getting started about wht guns to use...I'd always suggest the 38/357 as good combo as you can reload it cheaply, or, more importantly, if you don't reload, you can get decent reloads by the bucketfull for less than you can for 45 Colt....the general response was they wanted 45's because it was 'cowboy'.....never really understood why they'd ask for an opinion, when they already had their own, but that's a different story.
Anyhoo, the 38/357 guns you have are a very good start. At some point, you'll need to pick up a second revolver, and were it me, I'd try to match it as closely as you can to your current one. makes transition form one gun to the next easier. When I started, I got a good deal on a pair of 45's....only thing was, one had a 7 1/2" barrel, and the other was 4 3/4". Both good guns, but the transition between the extreme lengths was enough to really throw me off. They handled completely different....finally wound up rebarreling the short one to match to long tube, and things got much better, as I no longer had to think about which way this gun handled /shot, just yank and shoot.....allowed me to concintrate on hitting them targets that sem to come to life at the buzzer.....well, maybe not hit them all, but sure worried them a bunch.
Shotguns are a different matter. Choose what suits you best.....best advice is to go to some matches, as there'll always be pards ready to loan you their gun....this way you can try different ones and they do handle different. I prefer hammer guns myself, but I'm nostalgic in this regard....if I want to go fast, I'll pull ut the '97. Generally, I'm happy just being half-fast.
Your off to a good start on a battery, stay with them and try some others at the shoots, then you can make an educated decision on what to get next.