Techspec has soon great stick on rubber pieces and I have had a few.
I just emailed them about the F6C to see what they recommend.
They have two types for GoldWings so it shouldn't be too hard to get one for the Valkyrie
There is no way to protect paint on that bike regardless of place on it. The paint is low quality and even regular microfiber leaves swirls immediately. Even if you add protective film it wont cover the whole tank and uncovered places will look bad after some time.Also with time there is a chance that the film will either unstick(small parts of dirt will get under it and will scratch the tank) or stick forever (with time may crack or change the color itself or there will be noticeable difference between covered and uncovered parts because paint looses its depth of color) and you don't want neither of those scenarios.
Front fender even worse - too much pipes and forks around it, so pretty hard to keep it clean or put some protection. Rear fender has problematic spots around those passenger handles or whatever they called .
When I got the bike I thought that I will keep it super clean forever and will protect each millimeter with anything available on the marker but it is EXTREMELY hard and takes A LOT of time. I got the orbital polisher with set of super expensive cleaners, detailers and waxes and that was the only solution to keep it kind of protected After polishing and waxing it looks amazing and for some time dust cant land on it but still that is temporary solution and does not protect from minor scratches made by pants.
Another solution would be to put leather like cover on the tank but this bike does not deserve to be treated like that
Regardless of chosen protection, polish the tank before applying to remove existing scratches, swirls, marks, etc.