Wells first of all, 0.93 inches does infact make a difference when it comes to fretwork, but not the difference you might think, you'll just have frets that are thinner on the sides.
Secondly, if you are interested in investing money on that tool and it will be usefull for you in the future believe me, get theAdjustable/Arching Radiusing plane from LMI
To set it up, you will have to
-get a compass, (not the kind that points north)
-set the compass to the radius of your fretboard
-on a piece of card or stiff paper, draw the circle that has the radius of your fretboard.
-cut out the circle in a manner (you wouldnt have to but you could use the cutout for a understring gauge when shimming the floyd rose) so that you can use the cutout as a radius gauge!
-set up the plane and go
in my opinion thats the only presice way to achieve what you are doing, that radius gauge is very helpful for getting those weird radiused fretboards found on many guitars these days