Seaplane Rating Add-On and Seaplane Rental

Hi Group,

i have a question concerning a seaplane rating add-on to a Private
Certificate ASEL.
I'm interested in the ASES-Add-On to my Certificate, but what if i'd
like to rent a seaplane after the Rating Add-On, is this possible
directly after doing it or do i've to get experience with a CFI after
it ?
Are there any restrictions from the insurance companies concerning
PIC-experience on a seaplane, e.g. 20 hours or so to rent a seaplane
as a single ?

My interest would be to rent a seaplane and fly to the beautiful isles
of the Bahamas. Would this be possible or are there any restrictions
concerning the Seaplane or the Insurance Companies ?

Does somebody have any suggestions or recommendations about the rating
add-on itself, especially in Florida ?

thanx for now

Peter