I just (eventually) started my Cantonese blog. For Cantonese input convenience, I type on my iPhone and then post it to Blogger via Posterous. That means I have the same Cantonese content on both Blogger and Posterous. (I will hide one in the future to avoid duplicated content.) so I think using the same method for my English blog should be feasible.
After merging two blogs, I don't have to worry about differentiation any more. I don't have to think about which blog to post depending on the type of content. I can focus on writing instead of tools. If I'm with my Mac, I will use MarsEdit; If only my iPhone is available, I will use Posterous. No matter what I use, all content merges to my Blogger's stream.