I stumbled upon this and didn't want to forget it. Krenkel, who was known to be quite a fan of ERB and REH, apparently liked CAS well enough to illustrate a Klarkash-Tonian tale. Check this out:

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The illo is from an issue of Amra. I don't know of RGK ever being commissioned to do art for anything CASian, so this would appear to be a labour of love. Krenkel is still highly regarded by genre art fans.

Nice! Do you know which issue of Amra it's from?

Early '70s. It would take a bit of searching. I wish the complete Amra run was online.