Lets talk about flat springs!

[G.T.]

Hi to all! In my adventures repairing Lugers, I very seldom encounter 1900's or any Luger with a flat main spring. They are a bit scarce as George Luger was quick to find out that this was going the wrong way, and switched to coil mainsprings shortly there after? But now and then I need to repair or restore a flat mainspring equipped Luger, and it would seem that the flat springs are pretty scarce items. So, my first question before the membership is, just how many different strengths of flat mainsprings were factory made?
I'm pretty sure the 1900 would be the weakest, but after that, were the .30 carbines and 9MM Lugers equipped with the same spring? Does anyone have any experience with them that they can clear up some of the above questions? Best to all, til....lat'r.....GT...