I'm reading this now.
I'm afraid that the gearing isn't going to be affecting your cruising speeds as you seem to want.
A taller final drive ratio will help you cruise at a lower rpm than before, but it's still putting out the same hp to make that speed, so you just have a wider throttle position.
Gears aren't magic. They can't make your bike cruise faster. They just change the rpm it cruises at. It still has to make the same hp, has the same(or more) load on the engine, and the engine is limited by a percentage of its total output for cruising.
If we could all make our bikes go faster by a simple gear ratio change, then we'd all be doing 200mph
There's more to it than that.
It might help a little bit with some reduced friction, but it's only minor.
So let's get down to brass tacks.
How fast do you want to cruise on this bike?