"best" is not "best" when it costs more than needed
to do the job

Yea, that was my protocol in early years of boat ownership. Now, if
the materials cost isn't significant compared to the labor and hassle
effort, I always buy the "best" stuff at whatever I'm trying to do,
which would be bond strength if fixing hull holes. Also go for
user-friendly; epoxy doesn't give off fumes when polimerizing. Now,
if i needed a hundred gallons of resin for a job, I'd look close at
whether polyester resin would suffice.