Your message prompted me to go make some mapkeys that I have been meaning to make for a while now.
When I make (dims), I just use Ref Dimensions instead of Dimenisons.
I made a mapkey for adding a diameter symbol in front of a dimension like for linear dimsions and I put that in the Prefix part, I also created a (2) mapkey but instead of putting that in the suffix area, I but it right in the text window so the 2 don't cancel each other out. I am going to try this in workflow and see if it works they way I think it should.