I'm a 30 year+ recumbent rider (P-38, Metaphysic, M5CHR, Cruzbike S40), and have only done one SR series and that was on the P-38. I've done lots of double centuries and a couple 300K's on uprights. Plan is to do at least an SR this year and would like to do the SFR Adventure Series, and at least the Marin Mountains 200K
is an absolute no-go on a recumbent.
When I decided I'd start doing doubles on the upright ~2010 I got a Selle Anatomica due to Tom Milton's (SA's founder) association with the California doubles scene. The saddles were everywhere around then. After a couple doubles I gave up on it though ... it was comfortable on the first ride, but over time not so much.
I found a dealer in NorCal that did Selle SMP demos and worked my way through a bunch of saddles. There are a bunch, and the differences between them are very subtle. It's now going on 10+ years, and I have Selle SMP's on all my uprights. I was certain the Selle SMP Dynamic was the saddle for me after a couple test rides then riding the Sierra Century with it (and bought it), then did the Mt Tam Double soon after and I was dying by the end. I then tried the Drakon (very very slightly wider) and it felt good like the Dynamic to start, and was still fine by the end of a double.
I did ride a 200K last weekend on the recumbent, and looked at my 20% fewer kJ's than had I ridden it on the upright, and wondered if I'm making a mistake with the upright, but I'd like to get back to the social aspects of randonneuring, and that doesn't work when you ride off the front on the flat rides, or are perpetually trying to catch back up on the long hills. So at least for the next couple months, plan will be to let my butt recuperate during the week on the recumbent, and ride the Selle SMP's on the weekends.
So my suggestion would be go test out a number of Selle SMP's. I think they're broken up into a couple lines based on the padding (way less padding than the Selle SMP that was posted above), so find the line that works for your sit bones and then work through the variations to find if one perfectly fits. It's important to get the tilt just right. I can't imagine riding any other saddle now.