Well I'm sure there are Hydrangea experts, especially in the Hydrangea Forum that know more than I do but my Hydrangeas are doing well and I'm in zone 4B-5 also. So, for what it's worth, I leave the buds that are coming in alone. Let the plant do what it needs to do. They tend to get bigger (by that I mean wider and more new stems in a broader circle) every year so the new stems are good but old wood growth is good too.
Many people mention how lush my hydrangeas are by mid summer and I think one trick is supports underneath. Once they bloom those bloom heads are heavy (esp. after it rains) and they can droop down) so supports are a nice thing to add to help with that too. Hope they come out lovely - it sounds like they are healthy to me.

My hydrangeas leafed from the bottom weeks ago. The buds are just starting to open now. I leave my old wood for a good long while, just in case.

Thanks so much...I rec'd answers from both forums, and all the feedback is helping me to chill out.
I've got my fingers crossed and I'm sitting on my hands.
Now, if we could get just a little more rain here. I made trenches around both H's so they'll catch and retain as much water as possible, and I fed them some Miracle Grow acid-loving-plant plant food.