Indysteel gave you some great advice in her post about fitting & feel of the frame. If the 51 fits you in the Comp, it will fit you in the Pro. Mine is actually a 51. The feel of the ride will also be the same.

When it comes to components I agree with Cali, if you are deciding between the Comp and the Pro.If the Pro is in your budget, I would go for it. I can assure you will not be dissappointed.

As far as triple or compact double, I used my granny gear on my Dolce Comp a few times only so I do not see a problem using a "compact" double.

I cannot wait to hear how your trip to the LBS turned out.