Thanks, all for all the ideas and feedback. Really helpful! It seems like Specialized 3D saddles (one of which I’ve used and has been the most comfortable/manageable I’ve tried for longer rides up to 100 miles) and Selle SMP saddles are consensus picks. I’ve been testing the Selle SMP Avant but have given up on it – it gets uncomfortable (soft tissue pressure) after about 35 miles for me.
I saw this deal from Pro Closet and decided to grab the Specialized Power Pro Mirror for $30 off, since it rarely gets a discount. Hopefully this will be comfortable/manageable over 200 miles.