Thermoquad 1 3/8 center section on 1 1/2 throttle plate

Hi All

I have a Thermoquad (made from two parts carbs). When building the one good carb, I used the 1 1/2 throttle plate as it was in far better condition that the 1 3/8 plate. Not paying attention, I used the 1 3/8 bowl on this combination (Looking back at this, both carbs had miss-matched bowls/ throttle plates when I got them)

This carb runs decent (starts and idles better than any carb I have ever ran) but has always been rich when cruising (using a wideband+spark plugs to tell). I went down in jet size yesterday (adjusting the tree never yielded enough change) and really didn't notice any change, in fact its running a bit richer. Assuming I must have messed something up, I just took the carb apart and noticed my miss matched center section. Could this be some of the cause of my rich mid throttle problems? I am cleaning the 1 1/2 center section up now so that it could be installed.

So what are your guys thoughts? Could this combo cause some sort of odd signal issue to the primary circuit of the carb?