Puzzles #317 & #318 - Plus or Minus (Pentominous Borders)

Last night, TGE mentioned dreaming up a neat deduction in Pentominous Borders. Neither of these puzzles use that deduction, and instead were the result of me toying around with the type for a bit. Also, if you're here from puzz.link/db, remember to check back tomorrow for a penpa only puzzle.

puzz.link interface      penpa interface

This first puzzle came about from trying to find a minimal border solution for a valid 5x5. It turned out surprisingly interesting for its size and unfinished appearance.

puzz.link interface      penpa interface

Then I wanted to make a larger puzzle to post here at the same time, and spent a while toying with different themes before finally hitting on + signs, with the break-in. However I ran into issues resolving a corner with this restrictive theme and tried to make the rest work with just - signs, and was able to! It can take surprisingly few clues to make this type work- the deductions often have far-reaching consequences.