The design of altazimuth mount that I had in mind as being much better for refractors than the AZ4 Mount and Porta II Mount is well illustrated by the Unitron altazimuth mount, which was commonly in use some decades ago:
This altazimuth mount was a precise piece of machinery which was not particularly heavy, and it offered excellent precision of motion and excellent stability, even when it was used with a long-tube 4inch refractor.
cheers,
madbadgalaxyman