Only light pressure is needed. The tape will just give it something to stick too, in my opinion.
Yeah, same stuff under the bolts.
My favorite uses are stanchion bases and running lights. Consider something else (3M 4200?) where adhesive is needed.
Thanks pdqaltair. I've been using 3M 101 so far in places where I need adhesive, like the chainplate covers, which aren't through-bolted on my boat, so butyl wasn't recommended. Of course, I'm talking all deck stuff--I haven't done any real work below the waterline yet.