Thinning is essential. I had help from a painter friend, and his standard answer to all problems was more thinner (water). At times, he'd even mist the paint from a spray bottle ("mist" is what you want, not drops).
I did order the "tipping brushes" that SystemThree has on their website. They worked better than any other ones I had. We used two brushes, so I could switch to a dry one half-way through one coat of the hull. Three would have been even better, as they don't work as well when they load up. Washed and *dried* them between coats.
Rolled with short nap/foam roller with second person tipping the bubbles (brush held 90 degrees, featherlight stroke). We never let the paint sit even 12 secs before tipping, so it would still level after tipping. Anyway, we had no bubbles at all, except for some of the early coats where we occasionally missed a spot in tipping (practice helps!).
We did add one or two extra coats, so we could lightly sand the top layer at 1200-1500 grit and then buff it (3M rubbing compound followed by 3M Finesse It). That worked really well for us, and while we did have some upper body exercise, none of us turned Popeye
I did not use the clearcoat, just didn't occur to me, but I can see how that would look even more spectacular. The trial size containers were about right for the waterline, I think we used two.