I'm a big proponent of the s-hook method
, however, if your machine has a good brake this method is pointless. If you know how to use the 50/50 method you can compare the two and figure out which one you prefer. Quite a few people use the 50/50 or a boomerang. I've tried the boomerang and it works fine, however, on occasion they pop out of place, which isn't a huge deal, but with the s-hook that's never an issue. The 50/50 method was fine as well, but I simply prefer the simplicity of the s-hook. There was something about starting in the middle of the racquet and being obligated to use a starting clamp that didn't quite sit well with me, didn't seem as seamless as using the s-hook. Anyway, your opinion may be different. Try it and see what you think - it's a cheap experiment.
I'll let others address your remaining questions as I'm short on time. Good luck!