You can actually set the low side needle on a .91VRDF with a feeler gauge (.060) or a number drill (#53). Open the throttle barrel all the way (full throttle). Check the gap between the spray bar and the low needle with the feeler gauge or number drill. Set it so you can just slide the gauge in and out of the gap. I have never had to re-adjust a low side needle set this way. I believe this method came from Tom Cook (Jet Model Products).

When flip starting a .91, it will frequently start in the wrong direction. Sometimes a quick blip of the throttle will correct the rotation. I have never had one start in reverse when using an electric starter