Wasn't the big dish more of a main sensor than a deflector in TOS, anyway? Whenever deflectors are mentiontioned in TOS it is always in the plural, suggesting a variety of systems.
The notion of a single deflector dish is very much a TNG thing
As regards your ship designs,
Blssdwlf, they look very nice! I particularly like the inclusion of the clamshell shuttlebay doors on the back of the Reliant, it really grounds the design in that period.