The o.p. is throwing real money and time at this and it would appear the problem isn't completely solved. It could be as CFB surmises "not enough time in the saddle" or in other words "too much too soon". I am not one of those who believes in "the perfect saddle is out there you just have to sift through piles and piles of them until you find your perfect..." No, just no.
He may be a good candidate for SMP saddles. I can't justify the cash outlay myself. Tourists are the worst when it comes to being pro-active about getting up and letting blood circulate in the area under discussion. The best saddle in the world won't help you if you just grind away hour after hour.
Edit:
https://www.stevehoggbikefitting.com...ll-about-smps/