Thank you guys for all the help.
Lots of different ways to accomplish this.
No matter which way I go, I'm convinced these motors are a great way to track up to a 100 watt panel.
Maybe larger, since solar panels can be easily counterbalanced.
Just wind load problems where I live, 90 mph gusts.
These motors have many attributes of a commercial tracking drive in a compact, neat, and inexpensive package.
Worm gear driven, so no coasting/drifting like a TV antenna rotor (not to mention the hassle of an ac motor), slow enough so simple controls can keep up with tracking, built in limit switches, much simpler and cleaner than a linear tracker, just not as heavy duty.
Just so you know, I'm using this to run some solar powered attic ventilation fans I'm installing along with a re-roof.
I'm located in Southern California near the desert. With the relentless sun, I'm really trying to cool the attic by upgrading the ventilation, and using white shingles on the roof section that's not visible from the street.
This makes the solar tracking easier, since it's for the summer months. One axis will do just fine, but I need most of the flow later in the day during peak attic temps. Thus, the tracking to aim the panels all the way to dusk.
My other option is to just use a larger panel in a fixed position and charge two 6v deep cycle batteries.
This would help in cloudy weather, and enable running past dusk and drawing in the cooler night air we usually have here.
Anyway, I have a couple bids on Ebay for some used/damaged motors.
Once I get my hands on one I'll know more, but a permanent magnet motor would make this really simple.
The roof fans arrived in good working order, and the roofers start tomorrow morning.
I'll keep you posted after I get past the re-roof drama.
Again, thank you all for the quick replies and great ideas.