On my H28, I did a complete bottom job several years ago. Here was the process
Random orbit sand off all of the "old" bottom paint and barrier coat to gel-coat using 80 grit. Of course I removed gel-coat in a few places by accident to bare fiberglass, I didn't bother to fill any of the gouges since they were all minor.. Regardless, final wipe down with Acetone. 4 coats Interlux 2k, I used a foam roller, I had no issues with breakdown of the foam roller however, the recommendation of a 1/4" nap roller would get you to the desired thickness sooner. As mentioned it doesn't really matter how many coats as much as getting to the recommended thickness of coating. Because I was in cool freshwater, I chose hard bottom paint for a smoother finish, and applied it as soon as I could over the Interlux to achieve a chemical rather than a mechanical bond between the two materials.
When we pulled the boat this year (year 4) other than a mild power wash and a few flakes off the lead keel, everything was perfect with only a slime film but certainly no growth of anything.
Take all of the recommendations from this group and any others you can get, read the manufacturers recommendations, prep and then prep again and you'll end up with a perfect job.
Good luck,
Victor