Mr222 (Tylenol or Karen Valentine? ;-)
sit bone soreness is completely normal until it takes to your shape, I weigh 140 and I figure it took about 7-10 hours of 1 hr rides until the sit bones werent sore (I limited initial rides to 1 hr simply from being sick of feeling sore sit bones) I had also read that Brooks were more critical for getting the position right, I dunno but it seemed that way to me. All that said, I am more comfortable on my two B17s than other bike seats Ive had over the years (Im middle aged) so I like them a lot, but given how much you have ridden, you know enough about riding and seat position to adjust things with small changes. I too had some rear seat frame pressure, but then went too far the other way before figuring that out. Again, a seat is a seat is a seat, B17s work great for me and can ride day after day without any issues, but if yours really doesnt work after taking the time to try diff positions, then just use whatever will work.
I would say that given how much you have ridden, the real diff between riding hard and touring is that with touring, you spend most of the time seated, and not hammering so much, so more weight on the seat and hands-which probably equates to wanting to have your bike set up really well for you so as to even out the pressure "triangle" of hands, butt and pedals.
The attached photo shows a bike of mine that I have toured on, but also ride regularly. The seat/bars drop is similar to what you describe, and the B17 works fine, but thats me.
You mention back of leg near hip area pressure that never happen with road bike config", all I can think of is perhaps the seat is a bit too high, could explain some perineal pressure too? I dunno, just an idea. Like I said, rear seat frame, certainly seems a fore/aft issue like I had, and sit bones, classic breaking in issue.
good luck with messing about with it, as I always say, its only a seat so if it really doesnt work, get another. Sorry I dont have any suggestions for specific models.