I have not directly painted them-however- I have by error dropped some paint on them. It sticks well. We may thus infer that any paint used for plastics will work on this "J" channel
I used 1/2" for mine. It looks great
yes to a degree it will bend a little hope this will help
These j-channels are used as trim for vinyl soffits and vinyl siding. The are loosely nailed to the outer edges of the soffit opening or section of exterior wall, and the soffit panel or siding is inserted into the j-channel for edge support and a clean finish. I used this white 1/2” j-channel for my soffit and a gray j-channel for my vinyl siding.
Yes it is.
Some use roofing nails.But I find to use the staneless exterior flat pan head screws works better.
Depends on the size of your garage. What are the dimensions of your garage and what are you finishing off?
I only found white but you can check on line
If this is vinyl siding, it takes about .666 pounds of nails per square.
See an Associate at your local Home Depot store for availability and pricing in your area.