EDIT: I just noticed there's a GM9C800804BN -- which is a 1600 CFM version of the same 80 Kbtu, 80% afue, 17.5" wide cabinet!! So I guess my problem is solved! (I changed 1200->1600 below)
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Looking for advice on selection of a width for Furnace+Coil pair -- 17.5" or 24.5" --...