Cases; use only 38spl [not +P, the thicker case wall will squash the projectile when seated deep]. Nickel cases are easy to clean but are prone to cracking on the neck much quicker.
I use Win brass 38spl with good success.
Primer; There is only one to use: Federal 100 as they are the softest cup for light actions.
Powder; Try Bullseye as a first choice but others may shoot better in your revolver
Bullets; Get a quantity of various 148hbwc.
Now borrow a ransom rest, get all your gear together, including loading press, chrono, plenty of components, all the tools you may need to adjust dies, scope, and your gun of course, then plan to spend at least 4-6 hours at the range before you get that ultimate tight group.
Match revolvers are like cars and women, they need to be tuned to get the best out of them.