I hope I am doing something horribly wrong here. Please help if you can.

For years I have been squealing for this concept, to accommodate geriatrics like me with fading eyesight problems. See this link
https://forums.accuratereloading.com/eve/forums?a=tpc&s=...=857107494#857107494

Then finally I bought this HHA pendulum fitting with new generation BSA red dot sight for $200 and fitted it to my 5-year-old Hoyt Viper II.
To ensure it fits to all bows they supply you with all kinds of nifty adaptors and adjustable positions, so the fitting process went OK.

Then came surprise number one: the elevation adjustment works fine, because the pendulum simply moves the red dot sight up or down (just like a single pin sight). The windage adjustment, however, does not move left and right, but rotates on its own axis (being a firearm sight). This means you don't anchor in the same position. From peering around the string to a cheek far away from the string hand.
Problem number two was the flimsiness of the set-up. Not only the bracket, but more so the sight, once you adjust elevation. The dot moves 3" against the wall over 5 yards when I push it softly from left to right with the bow clamped in a vice.
So, I tried to shoot acceptable groups by first pushing the scope softly in the same direction every time (to take up slack for consistency). It shoots a 10" group on 20 yards! I wrecked 2 arrows against the wall in this process.
I am so disappointed.
What now?
Response from HHA?
Lochi.

What do you mean by it pivots? I see a standard BSA reddot with windage and elevation knobs.

Are pivoting the entire tube and weaver rail mount around the bolt that joins the angle bracket to the weaver rail to achive windage adjustments?

Rusty, by pivot I mean just what the scope itself does relative to the fixed mount. When you fit that scope on a handgun and adjust the windage, it literally shifts position of line as well. Looking at the scope from the top down, you can actually see that it is not parrallel to its base any more (when windage is adjusted).
Lochi.

I haven't used Redots on a bow, but I have hours behind them on firearms.

Looking at the scope and base assembly in the photos; it appears there is one central screw that holds the scope and its weaver rail to the angle bracket on the sight mount. If this is what you are pivoting around to adjust windage, then I would have to say you are moving the wrong thing.
There are acctual windage and elevation turrets on the tube of the reddot itself that you should be using. I understand that the elevation on the scope mount is a parrell link assembly so that you may never have to use the vertical turret, but the windage turrent would definatly be used. Set the tube so you are looking straight through it at your standard anchor point. Now adjust the windage turrent on the side of the tube itself (it'll have a threaded cap about 15mm dia. located at 9o'clock, don't pivot the base.

Rusty,
I appreciate your support.
The one I bought is the OL-MRS on this link

http://cgi.ebay.com/NEW-2006-HHA-OL-MRS-Multiple-Reticl...Z20845QQcmdZViewItem

I am in fact using the right windage Left/Right adjustment.
When you adjust windage on an ordinary scope on a rifle, you are effectively also forcing your eye to move horizontal from position a to position b. It just happens to be so little you do not realise it. On the bow a small adjustment far from your eye requires a huge horizontal movement of your head in order to keep seeing the dot.
Thanx again for your support.
Lochi.

YUP, that style definatly pivots the body of the sight. I have those on two of my paint ball markers.
Heres's a stray thought, bear with me, it might get muddled in the telling.
Assuming your bow is set up for true center shot, then the arrow, the sights, and the string should all line up on the center of the limbs when viewed from behind (standard shooters view point).
With the sight mechanically centered where is the dot in relation to the centerline of the string/limb/arrow combination?
If its off to one side can it be mechanically centered while maintainting a staight on view of the holoscreen?

Yes, I am contemplating taking parts from my old sight and fitting that to this set-up in order to shift the whole lot left and right after centering as you said.
Taking it to a bow shop tomorrow in case they are smarter than I am.
I sent HHA an e-mail with reference to this thread, but they do not seem interested. So much for service.
Thanx again,
Lochi.

Good luck with your sight. When you get it working as desired, please post what you did.