Opinions on RTV vs Gaskets on tranny pan.

You are correct that a lot of shops use RTV instead of a gasket, and that's fine on someone elses car for most transmissions.
The problem with doing it on TF's is that the pan rail on the trans has open area's along it and is one of the very hardest to seal up with RTV only.
Transmissions have filters for a reason, so clogging something up isn't really a concern at all.
I did transmission work for a living for quite some time, and I can tell you that we used RTV on most of them. (always used it on transmissions with a flat pan surface as it was company policy)
Everything got Dexron also as a company rule (unless otherwise requested or supplied by the vehicle owner.)
That being said, I wouldn't do on my own car because of the mess to clean up next time I took the pan off.

Just get the reusable gasket and be a lot happier when you never need another one. :-)