Hi,
The remote needle as supplied by OS does work but the
range of adjustment is limited due to the fineness of the
needle, if you feel you have to use remote adjustment then
go for the BVM.
Personally in 10years have not used remote adjustment on
the OS91 although have always mounted the needle remotely.

To adjust, start the engine, wind in until on peak then pinch
the fuel tubing between the needle and carb body for a split
second (you will soon get a feel for how long), if it dies then
its too lean, restart and try again until it dies and picks up, then
back off 3 clicks, this is about right, the main thing is not to run
lean or it will cut/blow the plug. Better to be rich and reliable.......
Mike