I haven't given the weapons much thought. Since there isn't a particularly definitive specification for the original Enterprise, I tend to view TOS designs as a kind of black box
problem - we can see what goes in and what comes out, but know very little of what happens inside.
Having said that, I reckon the Hecla has a bigger hangar bay than the Enterprise and a larger shuttle complement, it would therefore be able to launch/land more shuttles per decompression cycle. (I did toy with the idea of a destroyer version possibly being outfitted with a small fighter squadron, instead of shuttles.)
Here's those extra ortho's you asked for: