Welcome to the forum. I am a newbie here as well, but from what I've seen so far, there are plenty of contributing members who will gladly share their wealth of knowledge, opinions, and experiences with us.
Both Lyman and RCBS make good equipment. I personally prefer the RCBS equipment but others will have their opinions as well. Some will recommend the Dillon equipment and it's good stuff if you don't mind spending the extra coins.
7/8"-14 is the standard thread size for most reloading dies. Some die sets will work for more than one cartridge. For example, 38 spl. and .357 mag. use the same dies, but the 38 S&W has a slightly larger case O.D. The 44 spl. and the 44 mag. user the same dies but I'm not sure about the 44 Russian. someone else will be able to tell you.
Good luck with your choices. I'm sure others will offer their preferences as well.