[Djibel DR200]

At present I am running a 16 tooth gearbox sprocket & 45 tooth rear wheel sprocket. Pulls away fine. Fine in technical lanes. Just revs it's guts out at 45 MPH & above. How many teeth dare I increase on the rear wheel to reduce revs at 45-55 without over affecting the bottom end too much. IE Needing to slip clutch on take off & not having the agility in technical, low speed situations.

 

[Easy Rider 2]

How many teeth dare I increase on the rear wheel to reduce revs at 45-55 without over affecting the bottom end too much.

You have it figured out wrong.

The easiest thing to do, usually, is increase the front sprocket by one tooth.
You also could reduce the rear teeth by two or three but that would be harder to do and might require a different chain too.

I had a GZ 250 that I did a +1 on the front sprocket and it rode like a whole different (better) bike.
UNTIL I encountered a long hill at highway speed. Then I sometimes had to downshift.
No complaint though. It really was MUCH better overall.