I've only heard bad experiences when coating objects yourself for sublimation. I've seen stone that was printed on with DTG, so perhaps that's the current method that's being used, pad printing might be another method.
I have been in sublimation for over 7 years and I have yet to find a do it yourself coating that I would use for retail sales...just does not look right nor last right... some say it is okay...but for me it was just a waste of time
sublimation on thristy stones? 
