I'm taking out the anode again this week. I've ordered a "Cap, 3/4" NPT Female" and plan to install one of the 3/4" NPT iron nipples that I removed when installing the A7. I'll install with the Rectorseal 23631 paste, with the cap on top. The hole will be plugged!
If it still leaks, then I'll know the tank has a crack under the anode port. Or the thread has split (where I can see it)..
If it doesn't leak, I'll use "both Teflon tape and pipe dope" on the anode one last time. If it still leaks, I'll buy a new anode.
Thanks for the suggestions!
Rich