Weapons Dealer Contacts might be good too. Ravanor Krush can't be the only one he knows, after all, and in any case [i]he's[/i] back on Tuchanka.

Something like Prudent Negotiator might work well too.

I'm curious what you meant earlier by him wanting to do some good. What does he mean by it, and why does he want to? Krogans aren't exactly known for their altruistic ethos, even the level-headed ones. Unless maybe he wants to do good for the krogans specifically?