If the track is truly bumpy,
try mid-motor - even with low-bite.
The thing is that the weight behind the axle causes a lot of inertia on the rear end. It's completely true the inertia results in added stability. However, if you hit the threshold that the car gets out of balance - which inevitably the car will on a low bite bumpy track. It could be either because the rear end loses grip or that the car hits a bump very hard, but the end result is the same: the inertia that helped you before will make it very hard to correct the car because it's been corrected by a force big enough to unsettle it in the first place.
Every MM car I tried seems to suit me better than RM. It loses traction earlier and is more easily unsettled, but in a smooth, forgiving manner. It's as if the MM car announces the necessity to correct the car to keep it going in the right general direction, which gives you a zone to control how settled your car is. In contrast, the RM car pretends everything is in check, then suddenly points it's nose in the wrong direction like a stubborn mule and reports to you that you've exceeded the physical limits of the car's stability.
In the end it's all a matter of preference though - the story above is what I think of it, but best to try it is just to remove/add a gear and flip that gearbox around - it's what it was designed for after all! Of course, try an appropriate shock setup too, but it's worth spending some time on finding out your preferences on this. Once you feel comfortable with a car you'll get in the zone that results in consistency and pace
