I have an Olympian that measures 63.5 CTT, the Vent Noir I sold was the same size. I ride/rode them with narrow handlebars and skinny, hard tires (22 & 25mm tubulars). IMHO, handling is superb. In this large size, they are not the stiffest frame, but spin don't mash

. Your marginally heavier fork & stays might be a step in the right direction. Regardless, I consider AD to be an excellent ride. (as a comparison, an '85 SLX Merckx in 63cm was also not stiff, but a heavenly ride, for me.)
Be sure to update this thread. I'm always more interested in the ride report than the build list - unless it's a 100% original (or nearly) Euro component reassembly.