It's something I've always wanted to know too but think that, generally, it isn't exactly exact. There is huge carryover effect - a what the hell effect - with one armed swings and get ups, in that it gives you a base to work on other stuff. ie couldn't get anywhere near a 1 arm push up when I worked the 24.....and without practicing them could eek out a reasonable rep, not perfect by any means, with each arm once I got to regular work with the 32....without practicing them again. There is a tie in somewhere, where that is though will depend and with bodyweight strength....it may be your bodyweight itself that is the limiting factor rather than your absolute strength. And when you think about it, top of a one arm swing is a vertical one arm push up position, almost, although a totally different skill. I may have been more able to do a one arm because a) I got stronger with a kb and b) weighed less. It is your bodyweight that is highly variable, the skills you can apply v the skills and fixed weight of a kb.....which is why it is never going to be exact. Add in efficiency and learning the skills necessary it gets even more inexact. Just get strong and see where it takes you.