Where are you from? Go to a local match, find a mentor.
If you want to be "competitive" you probaly want 38sp.
Hard to beat the Ruger Vaqueros. Couple if options on grips/hammers. You won't need a back-up
Rifle wise a 66 or 73, from Cody Conager or Long Hunter. I have both. I like the 66 more, but I think the 73 is probably better. If you get a 66 reinforce the loading gate.
Bakail SXS by Johnny Meadows. For another $1000 you can get the SKB.
Get quality leather from a cowboy leather maker. I got mine from Johnny Meadows, j-m leather. You have to decide on cross draw or double straight hang. I use cross draw, if I was starting over would probably go with double straight hang.
Don't forget a gun cart to haul everything around with. The Rugged Gear cart us hard to beat. The wood carts are easier to customize or "pretty up" but the Rugged Gear just works.
Then side match, long range, plainsman, Wild bunch.....
4.5 years ago I had 1 Glock 9mm. Got into CAS, Glock us long gone, I have 28 cowboy guns! I shoot 3 times/ month on average. Greatest bunch of guys you will ever meet!