near focus is a value that must be absolutely out of not linear part of your vcurve or the slope calculation will be wrong. AI can compensate for it but not so much. Usually never go under 8 (if you are oversampled you must increase probably this) … best is from 10 to 12. If your system has a really undersampled resolution you can think to lower but isn’t the equatio more closest to focus HFD value and best is … this is exactly the opposite. The scope of vcurve is to find the slope in linear part of the vcurve and caratherize 1 HFD for step necessary for the local field. point under the near focus HFD value will be not considered for the slope calculation.
You can lower without problem the Vcurve lImit and the start focus for telescope with short travel in focuser, in this case also you get lower number of points for slope calculation , this is not a great problems … in this case better to do more vcurve to better refine the slopes.
Generally all the default settings in Voyager are selected to get in 99% of cases the solution.
All the best
Leonardo