2 gauge curved barbell PA and 8 gauge circular barbell nips. I like the curved barbell better than the rings, the dribble isn't nearly as bad when I pee and more importantly, it doesn't get pinched as easily. I find that adding a little extra lube to the tip of the condom not only gives me more sensation but also makes sure the condom doesn't tear.
I started with a 12 gauge PA and it was painful, if you get one, stretch it up to at least an 8 gauge as soon as possible. The smaller gauges are like one guy here said, cheesecutters, in other words, ver painful.