I doubt the tire/wheel combination on MV's spyder will fit many other spyders, or 356 for that matter. Those who have been around for a while remember that Thunder Ranch made basically two different styles of the 550 body. One that was the familiar Beck shape, and one that was something of a 'wide body' variant. MV has the wide body, noticeable by the front fender flares and wide rear clam.
So, unless one's spyder or 356 body is purposefully flared to accommodate 'wider-than-period' wheels and tires, replicating MV's good looking combination might be a tough fit.