I kinda felt the same way with the cut-out saddle I got with my road bike. Two rides was enough to realize that cut-outs weren't for me.
Trying your MTB's saddle would be smart, I think. On my road bike I now use a WTB Rocket V Pro Gel and it's very comfy. I also use a WTB (an older model SST) on my MTB.
Borrowing saddles or buying used helped a lot, since bike shops here won't let you return saddles you've already tried. WTB sells shops an inexpensive set of bright yellow test saddles, which I think is a great idea.
If you want a free WTB Speed She (I got it here for free as well, from abuelitodimetu) or a sweet dreal on a brand new Fizik Arione, let me know. I might also sell my Fizik Vitesse, but not 100% sure yet since that's my 2nd choice saddle.
Good luck with your search,
~Cari
P.S. Assos Chamois Creme is wonderful. I can't live without it and I don't think anyone else should have to either!