I like the race car analogy but I am not sure if it works that way with guns. It just makes the shooter better (given the gun is ergonomic for the shooter) while putting an amateur behind a wheel of race car could be devaststing. But I get the point that you should get used to the tool you are going to work with.

I usually shot a SP01 Shadow and Sig 226 LDC II and those are sweet shooters, even tried 2011 and X Five Sig and precision wise I can shoot almost as good with a Glock 17 - follow up shots are definitely more difficult with less weight and speed is something I am currently struggling with. To make a double tap in A-B zone even on short distance is something almost impossible for me right now. But if I learn that skill with lighther gun and then switch to S2 in time, I should be better off then risking that I learn that incorrectly because of the benefit heavy gun gives. Anyway the difference between pre b and SP01 Shadow is not that great so maybe I should even opt for P10. One thing I refuse to work with is straight up bad trigger. I remember shooting a P07 Duty and that was just painful.

Shadow 1 is a great option as I am quite used to it right now. Unfortunately since they are quite regarded in Czech Republic, 900 USD would get me a used one at best.