Well luckily in a Miata anything is a tight fit.
What I did was mount my Nikon N8008s, I used it rather than the F4s because of weight, on a Bogen monopod and used the Nikon remote shutter release.
I the n adjusted the monopod for the right height and wedged it between the transmission tunnel/console and the passenger seat. I also took the seat belt and got one wrap around the monopod before buckling it. I then also undid one of the camera strap ends and wrapped it a couple times around the stylebarand reattached it.
The combination was more bump resistent than my Bogen 3221 although it took a bit to set up.
This was a trial and error run and next time I will take some pics and post them of the setup.
LWW