As long as you have your center post, anyones tops will fit your rest. The only thing out of the norm about the Witchita is the diameter of the center post
As I remember, the post & top of the old Wichita are one piece. Several ways around that, neither of them much fun.
There isn't too much right with a Wichita rest, except maybe the price. I got one because of the 1" threaded post, feeling that might be better than the Hart 3/4" post for my 1K heavy gun, which weighs nearly 80 pounds. Since the footprint is smaller than a Hart, first thing was to bolt it to a piece of aluminum plate. I had some scrap; if you had to buy it, it would cost a bit. But if it's for a normal LV-HV, the smaller footprint is probably OK -- will help with benches like Kelbly's.
As I remember Joel (Pendergraft) milled down the original top to bolt on the new top he made for the HG's 7-inch wide forearm. He also made the rear rest for the HG, which is where the "windage" adjustment" occurs (legal in 1K HGs). If you don't mill down the old top, you need a new post. Might have to make it; not hard, just work. On mine, the original mariners' wheel broke, so Joel made a new one of those, too.
Joel does excellent work, but any one-off like this takes a fair bit of time, since you're engineering as well as making chips. And time, as they say, is money.
So if you can get a ready-made top for your Wichita, O.K. Watch the mariner's wheel, and put a bearing between it and the rest. If you need one custom made, Pendergraft Gun Works could do it, but he would probably need to wind up charging more than replacing it with a Hart to break even, so neither of you would be happy.
Do I like the Wichita with the 1-inch post now that it's all remade? Sure, but I've since learned that even with the 75-pound rifle, the old Hart with it's 3/4 inch post is just as good. Actually, with 1-K HG rules, I like a double post, double top bags even better. More engineering & materials & cost, but they track close to a RTB rail -- if they weren't sandbags but Delrin, they would BE a rail.
FWIW