Good to see this posted here rtate, I expect some good suggestions.
Josh has started us off well, and as I have heard your system, I bet your sealed servo sub would blend well with OB mains - can you remind me what frequencies you can bring it in?
It would be ideal to remove the lowest bass from the OB drivers, helps them manage their typically limited XMAX, and keeps them singing where they are happiest. I use an external crossover for this, but for trials the plate amp Xover in your sub will likely do the trick.
We will give it a run with my b200's, once the amp is complete too, to give an idea what those might sound like.