If you placed them so they were exactly equidistant from the primary LP, then, IN THE PRIMARY LP ONLY, you would get something approximating the imaging you get from correlated info in the L/R speakers. IOW, you would get a central image. It's not likely that central image would be "better" than, or even as good as, the central image from a single, centrally placed CC, but it would exist as a central image. However, at any other LP, you would lose the central image and you would get a comb-filtered mess.
You don't state what you are trying to accomplish, but if it's just more volume from the CC, then a better CC is the better choice. Sound quality is not likely to be improved with dual mono CC's.
Lombardi said it:
Perfection is not attainable, but if we chase perfection we can catch excellence."