Hey guys I'm still rewiring my garage (takes me forever to do anything

) But I had some problems with my GFCI breaker tripping, over and over until I could narrow it down to a bad fluorescent light fixture.
BUT doing all that running down to the basement just to reset really made me want to put GFCI outlets in the garage so I can just swap the breaker to a normal 20A.
Already got two of these: Hubbell GF5350IA
Brand any good? Got 'em cheap off Ebay NIB from some surplus electrical supply places.
In case you're wondering, I got faceless because they'll be mounted high on the wall where my two 20A lines enter the garage so I can run the GFCI's first and put all the other loads down-stream. I wanted them to be "GFCI switches" and nothing else.
Just wondering if this is a good brand or what? I considered going the even more cheapo route and using Harbor Freight stuff, but wasn't sure they wouldn't trip all the time. (or trip at all when they actually need to

) plus they don't have faceless ones.
Oh, and also wanted to know if there's any issue mounting two of these (for two separate 20A lines) in the same double-ganger box? Or would separate boxes be better?