240 volt 50 AMP for spa.
Running 4 wire all the way to sub panel and spa from main service. (Electrician said to use 8 gauge - planning on using 6 gauge)
Most people recommend a "sub panel" with a GFCI in it located at least 10 ft away from spa. The spa already has a GFI built into it.
Would I be correct in assuming there is nothing wrong with having two GFCI devices (one built into the spa) and the other at the sub panel? (other than potentially having one of them trip for "no reason" once in a while)

I don't believe I tested GFCI every month the way you are supposed to the last time the spa was hooked up and I plan on doing so now but may lapse... Wouldn't having two GFCI devices in the loop just result in one catching a problem even if the other "failed" to. (I understand the limits of what they can and can not detect.)
I also don't want to go messing with the way the spa was designed by trying to take the built in GFI out of the loop if I can avoid it...
Wonderbird

"Most people recommend a "sub panel" with a GFCI in it located at least 10 ft away from spa" this is not good enough, you need to find out what your city code inspector requires. They are pretty picky with distances and GFCI specs. You don't put 2 GFCIs on one circuit.