A question about ADS and blood circulation to the head

Okay, here’s the deal. I was dumb enough to buy a JES extender before visiting this page. It’s very badly designed (with the noose).
But to my question: it is easy to use, if I fasten the penis head really tight in the device. But that makes my head become cold and a little numb.
Now I’ve tried to change it so that I fasten the head a little looser, but then it doesn’t sit very well in the extender and sometimes even slips out (not often though), but there is no coldness or numbness.
Now to my question:

Will a decreased blod flow to the penis head have a NEGATIVE effect to my penis enlargement? Or should I just tighten it up and go for it? Because there’s no pain really… The head just goes a bit colder and I feel some numbness.

EDIT: And another question: Which way should I point the extender? The extender can be worn upwards, downwards or straight out. And I believe they have different effect on the penis growth.

Decreased blood flow, if it isn’t worse than numbness and a little coldness shouldn’t be a problem. But if you go cold, as in cold, and dark purple/blue as in oxygen starvation - then it is very detrimental.

You can always rebuild it the way nas_ana and babbis have (SuckXtender style).

Point the extender in various angles. Don’t get stuck in one way only.