Hard to say? My SLP boots have a more narrow shaft and are a bit more snug, but I like a little wiggle room in my shoes in general. I went TTS on Wyatts and have TTS on my both my remaining MMM. I could probably go down .5 in either and still be fine, esp with thinner dress socks.
I'll probably pick up another pair of SLP boots at some point.
PS thanks for the heads up, ordered the MMM to supplement my other black pair. My SeF don't really fill that need in my book.
I was actually close to ordering a black pair of SeF side-zips until I saw your pics; not that they look bad, but like you said I don't think they will fill the gap. I'll probably get some tan jodhpurs or something.