I've been using a pair of
Vello FreeWave Plus wireless remotes for 4 years now. It has swapable cables so the same set of remotes work for both my consumer and pro equipped Nikons
and my Sony a6000, just order separate cables. I can also set the receivers so that on trigger fires multiple cameras simultaneously. If I use Bulb mode it acts like I'm holding the shutter button down, so for remote wildlife shots it's ideal.
I know you ordered, but if the Shutterboss doesn't work for you I highly recommend these.