I see some minor aero mods that will help a bit, if you care to do them. Putting on flush mount turn signals front and rear. Removing the blocks on the fairing that carry the side reflectors and using reflective tape, like 3M Solas, will help (and you can increase your visibility, too). Then just look for other things sticking into the wind - pillion pegs, the loop at the rear of the seat, etc -and decide if you need them or not. Also look for details you can clean up - leading edge of the windshield, things on the bars, position of brake lines, horn, etc.
Cutting an inch off each end of your bars will probably reduce your frontal area.
The biggest reasonable aero mod would be your clothing - time for some tight leathers! Or at least try to make yourself smoother to the wind.
I read your post about gearing changes - all motorcycles, no matter how powerful, lose speed at constant throttle when you sit up at 70 mph. You are already geared toward maximizing mileage, but it might be worthwhile going a little either way to look for a sweet spot, or at least to chart what difference it makes.
You might try to reduce drivetrain frictional losses - one grade thinner synthetic oil, carefully aligned drive sprockets and well-cleaned and lubed chain.
Congrats on what you have accomplished so far.