I fish a 3/8 oz and 1/2 oz floats, with either 1/4-3/8oz weights under them if I am running a jig. If you're just going to run yarn/bait, then I would match your your weight to the required weight of your bobber to make it float correctly.
I dont like to run a leader much over 25'' or so. If I dont think visibilty is a super big issue for the given day, I will go short with the leader, down to about 18'' or so.
I run drennan style floats, but I also like westcoast floats.