Sometimes zero tail swing is achieved, in part, by widening the tracks making a ZTS digger less manoeverable.
Also, on principals of leverage - there are two things to achieve a counter-balance for the boom - one is to put a weight further from the centre (fulcrum) such as on a non-ZTS digger - the other is to put heavier weight nearer the centre such as on a ZTS.
So a ZTS digger may be wider and heavier than a non-ZTS of same capability.
J