RE: Where to buy 2 1/2
Most of the places that people have found that sized gutter have been individual hardware stores. True-Value; Ace; U do it etc. have carried it. Some stock it. Some do not.
I found it in two suburban locations near major cities ( Houston and Chicago). One was a True Value...the other an ACE. The ACE that had it was only a few miles away from another ACE that didn't carry it at all!
I have not heard of anyone finding it at the "big box" stores.. i.e. Home depot or Lowe's. Rich
p.s. Some guys have built the same planes but used folded 4 mil Coro. in place of the guttering.