For my $0.02 here is what I would suggest to keep the job easy, and get a good base. I would use one of the liquid / paste strippers made for fiberglass boats. We had a lot of experience with it, and for a do it yourself job, it will leave you very little sanding. (Other option is to have the bottom blasted, but if you do, find someone that uses either crushed corn cob or soda as the media not sand)
What you barrier coating looks like now is the base for a VC paint, (which was pretty standard with Catalina, and was the factory option) but at some point someone put either an ablative paint on, (what it looks like) or it could even been VC Offshore on top of normal VC paint. In either case the above treatments will remove it all. (if your using the stripper you could leave the barrier with a little care, add another coat and paint with VC,)
Once stripped down, you want a good barrier coating. I suggest Intrelux 2000e, at least two coats. You will find this a much smoother surface to put your paint on, even if using VC, as the VC tar is soft and will indent with pressure.
There are so many good paints out there, some very good ones that are cost effective you have to decide, and where you use the boat is a key factor. I am sure if you post your local waters, you will be flooded with suggestions on paint. If you use an ablative paint, use the old trick and put one coat of a different color on the entire boat, and overcoat with your color of choice. When you see the first color, it is time to repaint.
Good luck
Russ
