I started with antpool because it was the only available pool at first, after I used uupool during the period when antpool had a bit of problems with payments. These days i get payments from antpool, after upgrading the FW also goes very well in this pool.
As you say, the first slot is high priority
If you want to use antpool copy and paste the address that I sent you here above.
in the second slot I use uupool (if antpool dies) to continue producing.
in the third slot I registered at labs.f2pool.com (in case the first 2 pool die) but I never produced here.