I talked to Mojo extensively about "M44's" as a center channel and ultimately his response was "I personally think it would work fantastic. Make sure that they are oriented TWWWWT.
You are doing the right thing in my opinion. I wish I had this wisdom before I decided to pull the trigger on the VP150. But I suppose others can now learn from my experience.
This set-up is very versatile too. If in the future you decide you need a pair of bookshelves and don't mind parting with a centre, the M22s will work very nicely."
Here's the
link to his tests.