You don't need a workstand. You can either have a friend hold the bike, hang it someplace by the saddles nose, or flip it upside down using books or bricks to support the handlebar on either side of the stem.
To measure the wheel's runout (wobble) spin the wheel until the highest spot just touches the brake, then slowly continue spinning it until it's farthest away. How wide is that gap? If it rubs over a long length and the rim actually pushes the brake away, estimate and add that amount.
Centering a brake is also fairly simple, but before we go there, lets find out what the wheel situation is.
__________________
FB
Chain-L site
An ounce of diagnosis is worth a pound of cure.
Just because I'm tired of arguing, doesn't mean you're right.
“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN
WARNING, I'm from New York. Thin skinned people should maintain safe distance.