So what are the margins on spotting the jihadi spotters and beating them to the salvage?
Depends what drops - if as many hulk pilots do, the hulk was fit with a faction tank (pith, or gisti or pirate faction), then you could make enough to pay for a months game time

But it all depends on IF said gear dropped, as it is not a given it will.
If all the goods on a tech 2 fitted hulk dropped, you'd still make around the 20million isk mark. For example:
http://eve.battleclinic.com/killboard/killmail.php?id=3174031 (Ex corpie from my Sanctuary days lost a hulk to the first jihad last year); Only dropped 6mill or so, but had the potential to drop more.
The 20mill will for the ganker/jihadist cover the isk lost between the ship insurance and what you actually spent, so its a worthwhile risk
