I shudder when I think of OB, and my hat's off to you for taking this on. I imagine that one of the major challenges would be getting the subs inline, and finding a way to even get them interested in working for you. It seems they would, they would have to, give priority to all of their regular generals first, wanting to keep in their good graces for future projects, and by necessity put "one off" OBs at the end of their queue, knowing that any work done for an OB would likely be the only job they'd ever want done.
So finding the list of subs is one thing, how are OBs getting them interested in their project? Enough to provide bids? Enough to come and do the work?
I don't mean to be a downer, stating the obvious. I'm posing the question to other OBs in case they've figured out the answer. Or maybe this is just my imagination and in reality this is a non-issue. Hope so.