there are killmails with like 40-50 large skill injectors in corvettes because some ppl are just dumb, if you can use a t1 cargo scanner which is like 4k isk and you’ll know whether your target is worth bombing. I just don’t know if youll have the time though.
If scanning isn’t feasible its mostly just a crap shoot, you could also try looking up character on zkill but again might not have time.
Leopards are just HVT’s simply because they are rare and fast transports so ppl do often use them for valuables.
I don’t think a cruiser will have the dps to kill frigates unless they are auto piloting and then you might as well use a catalyst.