Inhibitors of the renin-angiotensin system for low flow POTS?

[Jenny TipsforME]

At the moment our herbs are split into three catagories:

cognitive function - we have a few but its hard to say yet.
orthostatic tolerance - hit and miss unfortunately
sympathetic excess/wired and tired - these ones are the most promising.

@ramakentesh did you finish your herbal guide for POTS? I'd be really interested to read it.

I've just started a Horse chestnut complex:
"Horse Chestnut 300mg
(provided by 60mg of a 5:1 )

Grape Seed 50mg
(provided by 5mg of a 50:1 extract)

Butcher’s Broom 112mg
(provided by 28mg of a 4:1 extract)

Rutin 50mg"

What do you think of that for POTS (and ME)?
I am interested in vasoconstriction (get disabling concrete legs and think need more vasoconstriction). My bp is on the low side atm. I take 5mg bisoprolol which isn't really working, waiting for appointment (UK NHS) to get midodrine or alternative.
BTW I find some of this thread above my brain grade!