I rarely do con commissions anymore as most are quick and I prefer larger/detailed pieces. I am on the list for a few but those are for "home" commissions.
For the WW I messaged Warren as soon as he posted it on IG. He messaged back that it was available and I purchased it before he put it on his website. We then discussed the back which was the first front and back he ever did. I then asked later if he had any other covers available and he showed me a few that were available. I chose the MJ because it was the best cover stock from images he sent to me.
Most I contact via DM through IG. They will either discuss availability themselves or point me to their handlers.
IG has opened a lot of doors for overseas artists. Warren is from South Africa, Gorken from Turkey, Chris Clark from London, Aury from Italy....all were contacted directly from IG. I did a lot of legwork discussing the CGC process as most were not familiar.