Vasodilator will help ease symptoms but it wont boost No2.
Increasing no2 intake will cover both bases.
POTS is lack of vasodilatory control....another symptom of poor NO2 status.
I have NMH and thought that that was failure to vasoconstrict, so I'd be worried about taking something that would be a vasodilator (in fact I'd just be plain worried, because I don't have a clue about physiology!).
Bit worried that people in the wrong subgroup might do themselves a mischief with this.
Delighted that you've had such success, though - congratulations!