I contacted him with a question about his "N-3" technique several years ago and he sent me a response along with an attachment detailing the process (obviously something he had written up before hand).
I contacted him a second time a few years ago after winning a feePay auction for 5 of his prints (RIDICULOUSLY low price ((about half of what just ONE would normally cost!) and he took the time to look up and send me all the information he had on them. He even wrote out his memories of making the exposures.
Mark seems like an incredibly nice fellow, might be worth a shot.