[CR]Italian Threading on my British bike!

Hello all, New member to the CR list, so I thought I would give a brief introduction. My name is Kirke Campbell from Houston, Tx. Been riding bikes as transportation since I was about 14, but have just recently gained an affinity for classic racing machines. The bikes I currently own are a 1984 (just barely out of CR timeline!) Bianchi Nuovo Racing (This is what it looked like new: http://bulgier.net/pics/bike/Catalogs/Bianchi-84/3.jpg) and a 1971 Mercian King of Mercia touring frame. It does not have original paint, but the serial number was confirmed with Mercian. It is currently built up as a fixed gear and is often my choice for the daily commute.

I plan on restoring the Mercian to a similar-to-original condition. I would still like to ride the bike, so I am avoiding NOS parts, although I might send it back to the Mercian shop for a respray. OKAY NOW TO MY QUESTION! My issue right now is the bottom bracket. The BB shell had been retapped to Italian threading and faced (sides if the BB shell evened out) so that the BB width is now about 66.5mm instead of the original 68mm. I plan to build this bike up with Campagnolo Nuovo record. I know I will need Italian cups but I am not sure whether I will need a 68-SS-120 spindle or a 70-SS-120 spindle. Should I be concerned about chain line? Front derailleur clearance? Also, what would be appropriate: the thin or thick (with rifling) walled Campagnolo BB cups?

Any advice would be much appreciated. And if anyone had any spare Campy BB parts that might help me out, please feel free to contact me outside the list.
Thanks!
--Kirke Campbell
Houston, Tx.