It should be comfortable..
I find that around the 40 mile mark some saddles start feeling uncomfortable. They might feel fine for shorter rides, but when you get tired you tend to sit more and put more weight on you rear instead of your legs. The big thing for me is width. I can use an San Marco Concor Light (135mm) and it feels great until I hit around the 40 mile mark then I start feeling pressure, and then my rear will eventually start to feel sore. So sore that it will carry over to the next day. I dialed in my width to 143mm, which is the width of a Selle Italia Flite or Flite Gel. I think saddles might be more crucial for flat rides, on climbs I tend to alternate standing and sitting and I move around a lot. On the flats, I like to stay in one place. I think a saddle should work so well it should be boring. It's just there. Shorts count also.