Is these tires sold only for 15" rims?
Are they good? Bad? Expensive?

Are they the only alternative if I want tires vider than 12" and a total high of at least 29"?
12,5x15-28 (a dimension i know exsist) is app 315/50-15.
I would like to have something like 315/50-16 or 315/45-17, but do these dimesions exsist at all?

The reason I want this is:
-I've heard 34 Ford looks best with at least 29" high rear tires because then they fills the wheel openings nice.
-I like a little larger rims than 15". No need for hitech style. 16 og 17" would do fine.