In Olympic lifting, as a general rule a good lifter should be able to clean 85% of what they can front squat (or stated more simply, clean what you front squat for 3 reps). So that can be a rough starting point, e.g., if you can front squat 2x24 kg KBs for 10, you should be able to swing 40 kg for 10. However, I don't think that this ratio, or any ratio, would work for KBs. The Olympic lifts rely on maximal power while KB work is more power endurance. Anything endurance related tends to be very specific, more so than with maximal strength events. Lance Armstrong tried to run a marathon and he did not do that well, at least not as well as what experts predicted he could have done. (Based on his VO2max numbers and other data taken from his cycling days, the experts said he should have finished in around 2 hours - essentially he could have won the race. He finished in 3 hours. Not too bad for an amateur runner but an hour slower than his predicted time.) Reason: he didn't run enough and relied on the fitness he built from cycling to get him through the run. It didn't work. So, if you want to get better at swinging KBs, then swing more KBs. Developing maximal strength will help somewhat, and developing endurance in your squat will help somewhat as well. But don't be like Lance - don't rely on fitness from one discipline to automatically transfer to another.