Hi Aaron
Attached is the photo you asked for. My platform used the same sectors as Ed Jones has. These are circular but the large sector is sanded so that it can ride on horizontally mounted rollers like Ed's does.
Ed Jones does this sanding with a circular saw sanding attachment. I used a jig mounted belt sander. The belt sander was cheap - I think around $40.
My first platform used the Warren Peters circle sector design. It worked but I found getting it to ride on 8 bearings very tedious. Ed's design and the VNS you mention are easier in that the platform top naturally sits on the 5 support bearings.
If you make a jig, a VNS is probably easier to build than a circle sector platform as there are less angled supports to cut.
I don't notice any wobble with the stepper motor on this platform. I think it's because the allthread gives a high gear reduction ratio. The stepper circuit is the one described by Nils Olaf Carlin:
http://web.telia.com/~u41105032/Stepper/Stepper.htm
It has a number of nice features:
Automatic rewind
A beeper sounds before the rewind
Correction for the small error caused by a tangent drive
Warning beep if battery power is too low
My friend Geoff did the electronics and he sadly passed away last year so I can't answer many questions about how he build the circuit. If you are interested though, we both corresponded with Nils and he was extremely helpful so you could email him.
Hope that helps. PM me if you would like to arrange a phone conversation.
I think Equatorial Platforms are a great ATM project. You can get so much benefit from relatively little expense.
Rod.