I have to say I very much appreciate this mod. I wanted to do something a bit similar but I don't have the coding skills required. Maybe it will gives you some new ideas for your mod:
My idea was to make salvaging time consuming: you win a battle, you select what you want to salvage as usual, but it won't get instantly teleported in your cargo. Instead, a cloud of debris is spawned and you have a progress bar to show the salvaging operation going. As the bar fill, you get a steady income of supplies and item, and sometimes a weapon you selected, the larger ones having a greater chance to be picked last. Only if you wait until the end you are guaranteed to get all the loot.
The speed of the salvaging could be proportional to the extra crew you have, and the number of marines, giving you an incentive to bring in extras even if it cost more in daily supplies consumption. Another option could be to suspend CR recovery to accelerate the salvage, though I suspect we don't have the right modding API to do that...
If you didn't picked everything, the remains would drift toward the nearest planet, star, wormhole or disperse after some time, whatever comes first. Of course there would clouds generated by AI battlers too, and other salvagers that can could poach them.
This could remove the need for the very artificial "boost if you loose"... If the victor want some loot, he has to stay in place for a moment. Also, battles in enemy space could be more difficult since you have to stay aware of other fleets while salvaging.
That's pretty much it, I hope it will gives you ideas for your mod, and I hope to see it pan out!