I never see anything about setting the FL. I know its used to calculate FOV of EP. I would think this parameter needs to be set for the FL being used for Envisage to compare the guidescope FL with the main scope FL. I use an Orion short tube at f5/400mm and a 12-in at f10/6.3/3.0 and Have tried the 6.3 in combination with the f3 to get about an f1.8-2.0. Envisage locks right on for autoguiding in polar mode. No adjustments required.

John