Here are two little hacked contributions for you… The first is perhaps an alternate ability for a custom playbook that resembles a Slide? or perhaps the Spider? It’s going in my Runners in the Shadows playset, and I feel like it could work well as an add-on for all you scoundrels too. The second is a little reminder handout I use to be a more consistent GM.
Deal Shark: You are not affected by quality or Tier when you negotiate extra payment for a score.
This ability turns you into a shark at the negotiation table; you always land a sweet deal, either by easy confidence or ferocity. Without it, attempting an excessive negotiation (asking to increase it by more than the initial offer, for example) would only insult potential business partners.
Which I wrote because I defined “excessive” at my table, and once I set a limit, the players will want to break it. And the way I figure it, a negotiation for desperate action with equal factors theoretically should cap out at double the initial offer (because anything else would be uncivilized), or the offer +4 (because a controlled negotiation ought to be for the minimum increase, or an offer +1; and thus get you offer +2 on a crit). So, I extrapolated that and made the attached result table as a play aid, which you could probably edit for your own, adjusting the scale I wrote by 1 or 2 to reflect your table’s lighter tone when it comes to this stuff. YMMV if you like to willy-nilly decide, but I like to be transparent and consistent with my rulings when I can.