double carb setup installed (looking for advice)

Not even close, no. If your carbs are imperfect, don't pass "Go", don't collect $200 (you'll need those dollars for the carbs); go to Jon Hargrove.

As to your kickdown issue: what's your kickdown linkage setup like?
not really positive if im looking a problem in the face or not, but linkage is identical to when it was a singular 1 barrel