I watched an Epifanes demonstration on a friends boat. 2 part, the rep. thinned with the prescribed Epifanes, very carefully for the conditions. The goal was a roll without tipping, which he has great success with. He used a 6" foam roller but I can't say the brand.
Beyond thinning carefully which is intended to achieve a slow flow out, his method relied more on technique than coating.
He carefully rolled out the excess on the roller. Then he rolled 'thin', getting thin and full coverage. Then he finished with vertical rolling.
You'll see here, with the boat pointed to the Southwest, the starboard topsides is still in the shade.
He did one side, my friend rolled the other side, once the sun past the bow.
My take: I didn't see any time savings in not tipping as his rolling technique called for several passes. It's was a good finish, but not a great one. I could see the
orange peel surface left by the foam roller. Had he started earlier in the day (he was on a tight schedule), a little cooler in the lower sun, the coating may well have flowed out perfectly.
I think tipping would have improved the finish however different conditions would have made the biggest difference in the finish.
With 1 part paint, I prefer a full sized foam roller (nothing fancy) because I want to apply my coating quickly, and tip right behind. The last time my daughter did the rolling for the first time. Sort of an experiment, but she's had some experience painting. The key was timing on her part: I'd ask her to wait or speed up as needed advising more or less paint. I followed with a tipping brush.
The day was perfect, cool, overcast, windless and not too dry. The Easypoxy continued to flow out behind me further clearing up brush strokes.
It was a good coating. It took about 4 hours to roll and tip the 38' topsides. Time in prep, taping, boot top, etc, is another matter.