Interesting! I started with a BMBH and have added a BB, and you've gone the other way round! I got a BB because I thought it would be slightly better for winter use, when I could pitch the tarp more steeply and not worry about the spreader bars rubbing. I figure I may use the BMBH more often in summer, with a flatter pitch tarp and better views.
Anyway, back on topic, I got two sets of whoopies from AHE and use one on the bridge with straps/marlin spike toggles. Very similar to what you're describing and it works fine. I reckon you'll be OK.
I have the original tri-glides if you'd be interested, but personally I'd recommend another set of whoopies if/when budget allows. I found the tri-glides and webbing to be quite effective, just not to quite so convenient or user friendly.