fire extinguisher location

I prefer a full suppression system but time constraints are against us to finish in time for September at CMP. Currently the plan is to have two 5 lb bottles mounted in the car, one behind the driver, accessible from outside the car and another for fast driver access. In the Miata there isn't a lot of space to put anything, and we really only have 2 places it could go for easy driver access. One is the other side of the trans tunnel and the other is on the driver floor against the front of the seat. There may be issues with both places, like if on the trans tunnel, there is a risk of it rolling away out of reach, and in front of the seat there could be issues with hitting your legs on it. I have tested ingress/egress with it in front of the seat and there is no problems there, and access is the same surprisingly in both locations (I can have it in both hands and aimed in under 3 sec). any opinions for or against either location?