Thinking outloud about donuts, Rims that is

[WAAF]

OH TAY..
Because my truck now has the gas tank underbed.. and the bed will be home for a spare.. I'm thinking donut..
not in the new car sense.. cause anyone thats used one.. never ever enjoyed it..
so I'm thinking a donut rim with a narrow and fairly lite tire.. say a dragracers front runner tire tall but narrow..

anyone know what size donut is in astro vans 15" 16" 17" 14" etc
I'd think that the vans and wagons (92 up) might have a donut that work..
yes I could buy a aftermarket front runner rim.. but cheap is good.
anyone of hand by chance know the rim sizes used on these..
google was zero help.
oter idea is a swing out mount like a jeep.. body armor make one that mounts to bumber and not body.. though of use'n that idea to build one.. just unsure of what it look like on the truck.. centered would look to much like a continantal kit.. and not a fan of blocking the grill..

thanks..