Update #2
I ordered the Powerstep, after contacting Dexter. They said that it should work fine, even though it was for sizes 9-13 and I wear size 7 2w.
I tried it tonight and it went on the shoe fine, but when I tried to bowl with it, it caught on the approach worse than the old sole.
I only tried it 2-3 times, because I wanted to make sure I could return it. Probably, if I practiced with it for a while I could get used to it, but I think I would rather just buy new soles every year or two, than wear that giant thing. After taking it off I tried the T 5 again, and it worked fine.
Also, Dexter is supposed to be sending me a replacement for the damaged T 3, although, I guess the T 3 is discontinued, because they are sending me a T 2, which is replacing the T 3.
I wish I had realized what a problem the SST-8s are for someone who drags their toe before I bought them.