How much hq % to afford selling jinxed at 20mil?
It's not the HQ% that makes the shields insane, it's the (up to) 80% material retention.
If you get 5 shots at a HQ per set of mats, and your HQ rate is 1/40, you can expect to HQ for every 8-10 sets of mats.
It's compounded on jinxed, because you can apply that to both synths. Jinxed wristbands, for example, cost about 1.6M to synth a hexed wristbands. At T1 with final shield, you can expect maybe 1/13 chance of HQ. Factor in that you're only losing 1/5 of the mats, and you may be looking at ~3 sets of mats per hexed wristbands -1.
Then, you have a 30%~+ chance of the T2 synth to make Jinxed. With only 1/5 chance of losing mats, you're going to get a HQ out of almost every hexed-1. The shields utterly demolish the costs associated with producing jinxed items.