with an additional bomber wing targeting the navigation subsystem the Sath would have been pinned in place for a short while while the shivs repaired the sath's jump capability.
Wait... destroying the nav subsystem prevents a ship from jumping out? Are you telling me I've played heaven knows how many FS campaigns over more than a decade without ever noticing this...?
Right now I feel like an idiot.

Well, back on topic, the Sath has more than decent anti-fighter weaponry, so don't underestimate how many pilots you would lose in such an attack. Remember we're not talking about a single Juggernaut, but about more than 80 of them.
Because we don't know how the Shivans organize and coordinate their fleets?
Signals intelligence is effectively peering into the future; that's the thing that makes it useful. The enemy announces what he will do next. Tactical signals intelligence, while still useful, has less lead time to react in and isn't as valuable as strategic signals intelligence.
At the ultimate tactical level, ship to ship and fighter to fighter, it's more useful to keep the peons from talking to each other and their commanders than it is to hear what they're saying. Face to face, jamming is king. Fleet to fleet, reading the other guy's mail is.
Ooooooh! Now me understands el castellano...

Seriously though, thanks for the answer. But I still think ETAK could be used for both purposes.
Regarding the Meson Bombs, the freespace wiki states that only 17 of them have been produced so far.
Besides, objections about my plan said even a Mjolnir with reinforced hull would be too fragile to be tactically useful. Well, if I remember correctly, Meson Bombs were even
more fragile. And if only one of them blows up too early without reaching its target, you lose everything you have near it, including the escort and other Meson Bombs.
also note that the harbinger from FS1 does about 10 times as much subsystem damage as the Helios so that could be readily used to disable the sathanas if any such torpedoes still exist; if not, those could possibly be manufactured too.
I know. The Harbinger is right below the Apollo in my list of
"Things the Alliance phased out with absolutely no good reason".