If you're fitting the 23mm R32 bar to the struts properly as you said, then firstly, thank god someone is doing things properly for a change

With the R32 bar up front I'd definitely go for a 28mm neuspeed rear, anything less than a 28mm and you won't get the nice change in balance that a rear bar usually gives due to the front being pretty big.
Run the 28 on the mid setting and it should be realy nice for road use, and crank it to stiff for track action or a bit of fun
