I don’t have technical info such as mathematical formulae for you in terms of percentages of gradient or degrees of banking, but suffice it to say that with low ground clearance you will have to make any changes gradual…anything too abrupt and the front or the rear of the car will scrape on the track. My experience on this is more with slot cars than RC cars.
I suggest tilting your car forward until the underside of the nose hits the ground, and tilting the car backwards to see how quickly the underside of the rear of the car hits the ground and if there is little movement before it hits the ground then you can use that as an indication that your track contour changes must be gentle and gradual…there should be no limit to the amount of banking you can use, as long as the cars get a chance to gradually get there rather than abruptly.
Obviously if you were running off-road type RC cars that have much more clearance, then moguls and jumps and banks are practically limitless.
I’m not sure you car relate RC cars to real cars when it comes to your track design and I suspect that as gradual as you will have to make your track contour changes, they can likely still be more dramatic than real racecar tracks. Example, if you have 1/4 inch of ground clearance on a 1/10th scale car, that would be like having 2 1/2 inches of clearance on a full size car, and we know that F1 and Indy cars are closer to the ground than that, plus at speed they are being pushed even closer to the track due to downforce, which RC cars will not be affected by.
I don’t know what you are making your track out of, but if you can feasibly do it try a little experimentation and before long you will know how extreme a contour change you can make before the cars bottom out.