It depends on how they did it, but probably a 10" wide rim with 11" to 12" tire. The stock wheel openings will limit how tall the tire can be depending on ride height and if the axle is centered in the opening.
Stock Vega tubs would be about 235-60-15 or 9x26 on a 7" or 8" rim, most mini tub jobs add the width of the control arm bushings on each side. Your axle width will only determine the needed wheel backspace. The width of your tubbs to the outer wheel well minus the clearance will be your tire width.
There is a tool made by Percys that is used to measure tire fittment.
IMG_1082.JPG
You do not have the required permissions to view the files attached to this post.