So the bang is the forks topping out. Likely that with the combined rate of spring and air your rebound travel is under dampened. Not much you can do to change that with out new fork cartridges. You may find better results by backing off the air pressure some. This will reduce spring rate and slow front fork extension speed. Unfortunately while the R3 needs more fork spring rate, it needs good dampening even more. Heavier weight oil helps but it is not quite enough.
Forks need set in just like rears. Too little and when accelerating the forks top out. When this happens, front tire loading changes abruptly as now the weight transfer to the back tire is lifting the wheel and tire from the surface (no more sprung weight left so un-sprung weight transfers rearward.) This works okay drag racing but is not so nice when rolling into heavy throttle mid-apex.
With stiffer springs and more dampening, you can increase fork set in which improves both handling and ride quality.
As Barbagris mentioned an accumulator between the two forks will insure that the forks are pressure balanced, and it reduces the rate of progression in pressure increase due to the volume reduction from the forks compressing. This would allow you to adjust set in height without as much increase in spring rate. (20 psi to 40 psi versus 20 psi to 100psi, for example, depending on fork air and accumulator volumes.)
As to the function of dampers under pressure, increased air pressure reduces the volume of air entrained in the oil. So, in twin tube low pressure gas designs, the shock will perform even better than normal, as these shocks keep oil and air separated (shock OEMs use vacuum de-gassing to reduce air in the oil when they assemble shocks, but some always remains.) In emulsion shocks, the oil and air are combined so the valving is designed to function managing a fluid that is somewhat like shaving cream. When this type of shock is put under pressure the air bubbles in the oil are reduced in size so the effective viscosity can change dramatically (the whipped cream can turn back into a liquid.) Thus emulsion shocks use a compressible fluid versus the uncompressible oil in twin tube or high pressure monotube shocks. Therefore, they are extremely sensitive to static pressure changes and will become very stiff if the fluid condenses back into a liquid.
Most forks and old twin tube shocks with no initial internal pressure are intended to function with uncompressible liquid oil, but when used extensively the oil and air begin to combine (are whipped into a lather) so the dampening goes to mush. This phenomena is responsible for fade much more than the minor viscosity change due to the oil getting hot.
If you think I am wrong about the cause of fade, keep in mind the extreme pressure drops created with a high speed high pressure liquid flowing through a tiny orifice. It tries to expand. If the fluid is a liquid with no entrained air, it will remain a liquid but there will be voids in which there is no liquid. These do not grow in size and quickly collapse (same phenomenon as cavitation.) However, if there is entrained air (microscopic bubbles not seen by the naked eye) those bubbles explode in size turning the oil into a froth. These bubbles collapse over time too, but if they are generated too quickly and the oil viscosity slows their ascent to the surface sufficiently all the oil in the system foams. Imagine blowing air through a soda straw into a glass of soapy water. What happens?