One more variance in your "Different saddles for different butts" statement. Don't forget " and different horses"
The different racquets would be the " different horses" part. I find some, not all mind you, strings play/feel different in different racquets. Not a biggie to add but I like your statement there.
Also , no to just Jack here but to everyone, I don't understand buying strings that only last 4 to 6 hours of play. Even at restringing your own racquet, after a while I would think you would get tired of doing that so quickly with any string. If you have to restring your racquet that often with a string I would really try to find a different string that plays close to that string but lasts a lot longer. Of course, that's just me.