Been back and forth from 8.25"/8.375/38"/8.5" for over a year now; I like to keep my trucks the same width as my board.
Currently, I'm riding an 8.38" (8.6" before that and 8.375" before the 8.6) and just switched back to ACE44s w/the mag baseplates from Theeve 5.85" TiKings as pivot cups are no longer snug fitting in either baseplate, sort of a weird ride.
I forgot how
amazing ACEs are.
Anyway, I put my ACEs on the 8.375" and it's a good fit (still thinking of dropping down to 8.25") - the difference is so minimal, 0.125 / 1/8", but I'd rather have my trucks UNDER than Frankensteining out the sides
That said, I setup my 8.6" with Indy 159s (8.75") for use in the bowl and don't notice the over hang at all. If I didn't get wheel bite when using Thunders, I'd get a pair as the 149's axle is indeed 8.375" as most DLX shapes max out at 8.38", with a few exceptions (hell even Zero/Lurkville use that 8.375" shape as they use the same wood shop in Mexico, so no coincidence that Cole rides 149s and 8.375"decks).
If it were me, and I wanted Indys in the 139/149, I'd wait it out as the refresh for those sizes with the new/tweaked stage V-VII geometry should be coming in January.