Offered: 53 Moser

That whole drop a size thing on track bikes is a point of dispute I'd say. A lot of places say that isn't the case. The top tube may be higher from the ground but then of course so are the pedals. For a normal track bike the same as your road size will be fine. Anyway this is a moot point. A 53 isn't going to fit you if you are 6ft, and showing that much post on a classic'ish' bike will look odd, think how long seatposts were when that thing was new, 19 or 25cm.
At a guess I'd say you need a 56 and remember to always check if the measurement is centre to top or centre to centre or you could end up buying a bike that is two sizes too small.
higher BB, means higher relative TT, when means the standover height is higher. so unless you want your nuts in your armpits, drop a size or two.