Dan, why so low? More speed? I am working on my wheel pants and I was thinking of cutting them higher to avoid problems with bumps or snow.
Yeah, drag reduction. I have no quantitative way to tell you if it's worth it.
Three details....
A-model clearance is less critical. Tailwheel models put the ventral section of the pant close to the ground while A-models maintain a more or less level waterline.
Here's the pant being fitted on the bench, level waterline. If I recall correctly there is a 3/4" spacer block on top of the tire for this fitting. Plenty of clearance under the pant, right?
However, load the tire with gross airplane weight, set the tailwheel on the ground, and this is the real clearance:
Neal Willford wrote an excellent series of design spreadsheets in Sport Aviation. One dealt with landing gear design. It included a calculation of tire compression for a given weight, landing G load, and air pressure. Most owners would be really surprised to learn how much the tire can be compressed during a firm arrival. The numbers suggest the average RV is grossly under-inflated; I run 50 psi. In addition to maintaining wheelpant clearance I believe it also greatly reduces stress on the tube.
The rubber is cut so it almost touches the tire sidewall, another attempt at drag reduction. Might not be such a good idea with an A-model, as it limits airflow for brake cooling. For sure I'd want viton caliper o-rings and MIL-H-83282 fluid.