nope - very popular modification on tin boats.
The problem that I see for your item #2 is how far it will
protrude past the hull surface. Take into consideration that
your metal is only about .080" thick.
I have used this type on two of my boats. Only because it is readily available.
Before you apply your caulking, install the plug, turn the boat over,
and grind it down smooth so it won't protrude out from the hull very far.
Remove only 1/8" or so. (just an option)
With your item #2, it looks like you can not grind any of it off to make it more smooth.
Jus my dos my centavos