I don't think the caliper clearance is an issue, only reason to space the wheel out is to keep it aligned with bikes center line.
Here's something to consider, NONE here mentioned or tried the HawkGT mounting method because NONE have probably ever removed the wheel from the Hawk. Well, here's food for thought, Hawk wheel is held in place by a bolt that passes through a center of the axle, than a nut holds the wheel in place via spacer. How difficult would it be to drill and spline the hole through the center of VFR axle and use a large bolt/spacer and nut to mount it HawkGT style?
as promised my Hawk/Ducati project pictures, got sidetracked with all the other bikes so I left it alone for now
in the back is a 748 lower triple modded with CBR900RR stem to fit the Hawk
left front is the sleeve insert, on the right is Duc eccentric with 5mm ring pressed on it for an offset
on the bike
I'm using Duc cush, the upside is that there are many lightweight aftermarket parts available for Ducati set up, downside is that Duc's have always used very small sprockets, 38 rear is stock, had heluva time locating a 43t rear, also have to use aftermarket cush for that, Ducati cush-drive consists of rubber insulators inserted on to a sprocket, dealer does not carry sprockets bigger than 39t (IIRC?) so I'm using the Fast By Ferracci carrier, got a sprocket from them as well, must have been for a stunt bike.