Stay of Execution is a rampant abuse of what's almost definately a bug, giving you infinite Regen 6 for the one-time cost of 14 Dust, which is small enough to be cast via bloodweaving. Regen 6 is the highest useful level of regen, which is able to regenerate your entire health bar in a second (1HP/tick). You can bloodweave after this spell is cast, in a move I call Atrophic Bloodweaving, allowing you to bloodweave any spell costing less than 20 dust for effectively free.
Mind's Reflection
64
32
Power Distillation
0
White Sun's Zenith
Mind's Reflection
6
10
-2
Power Distillation
Multiplicative Distillation
6
White Sun's Zenith
This works because Hex doesn't boundscheck potency. The first White Sun's Zenith gives you Regen 0 with infinite duration. Normally this would be useless, but vanilla's potion shadowing mechanics allows us to effectively upgrade the potency without reducing the duration through a second White Sun's Zenith. A duration of 0.06 is used on the second Zenith since Hex doesn't actually apply any potion effects with duration 0.05 or less.