Hello;

I need to replace the seal on my garage door. The seal slides into
two grooves (called "T-ends", I think) on a retainer strip, which is
in turn screwed into the bottom of the garage door.

Right now the screws are screwed in from the bottom, so that the seal
covers the heads of the screws. The seal is easily removable, but I'm
not sure how to insert a new seal. Do I remove the retainer, slide
the seal into the retainer, and then screw the retainer onto the door
with the screws facing the opposite direction (pointed ends towards
seal)?

Or would it be possible to leave the retainer on the door, and slide
the seal onto the retainer from either side of the door (there's about
1 1/2 feet of space on either side)? I don't know if this would be
possible as I'm not sure how these seals are packaged and whether they
need to be fully straightened out in order to slide onto the retainer.

Thanks in advance.