[T3] Battery Type- 063?

[Mark Seaton]

Hi, my battery is failing and I'm looking for a replacement, but what 
type should it be?
The one in there is a 36Ah Bosch, model no 536 046 030, but I can't find 
another anywhere.
The 063 type seems to be a very popular battery and has the same 
dimensions, but has larger capacity up to 45Ah.
Can I use one of these? Would it fit? Would the extra capacity be a 
problem- I'd have thought it an advantage?
Car's a '73 carbed fastback.
Thanks,
Mark