As someone with multiple Shields do you have an more info on your whole setup on the Shields? I have all my roms on a NAS already but every time I go to set this up, either with straight up RetroArch, Hyperspin, ARC Browser I'm always coming up short. Running out of space on the shield, roms not launching, front end issues, etc. I think HyperSpin was the closest I got but that's so unruly however it at least allowed everything to run off the NAS for the most part. I want to say I have the 2017 version with no sd card slots just USB.
I mean I could just use a P3 but the Shield has so much more going for it!