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I'd agree with Tony – auto guiding is more important than PEC. I believe that on most small mounts, the worm/worm wheel makes a single revolution in between 6 and 8 minutes, depending on the number of teeth of the worm wheel.
With auto guiding, you can correct for Periodic Error (PE) during the worm revolution, provided the PE is smooth and doesn’t suffer from large excursions due to poor workmanship, backlash, etc. That is, you would want any gear errors (PE) to be slow and smooth, so that when you calibrate the auto guider for an imaging session, it has a chance to guide them out.
If the PE is large and jagged, then long exposure astrophotography becomes very frustrating and unsatisfactory - in fact, almost impossible.
I also think that starting out with an 80mm (presume f7?) OTA giving a focal length of 560mm is a great way to start – you’ll get some good results without too many frustrations and set backs.
Cheers
Dennis
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