It looks to me as though WE might be able to take larger BG than an equal sized SMB, though this is completely subjective and I'd like to hear the opinions of others more familiar with both species.
From studies I have seen, when available WE will focus more on fusiform fish like shiners and minnows. However, if they are not available, spiny/rounded fish like BG will be eaten more. I have no doubt WE will eat smaller BG, especially when they are abundant. However, I don't think they make any better of a predator on BG than a SMB of similar size. I think you will also find, BG and WE tend to inhabit different areas of the pond at the same time in general. Again limiting WE predation on BG.
