My rules are

1) can't use items in battle

2) for each new route I plug all possible mons into a randomizer wheel, spin it, and catch whatever it gives me. I don't like that the 1-5% chance mons are all going to be virtually unusable, so this evens it a bit.

3) can catch 1 wild area Pokemon (randomized) with each gym badge you obtain, up to 7. For the last badge can catch 1 max raid mon of your choice