I don't think either could defend SGs on a consistent basis.
I understand the thought here, but we've got four legit SGs on the roster already. Is Green going to add more to our lineup than Bradley or Lee (or even Terry or Barbosa)?
I'm not against it for a few plays here and there, if we're trying to create a mismatch (i.e., an offense only possession where we post Green against a smaller SG defender). However, as a serious strategy to be used for long stretches, I think it's flawed.