Th Domane is a fine choice. You get all the benefits of the endurance fit and you get ISO speed to smooth out the chatter. You could spend less but you specifically chose the SL5 as your starting point, so it would seem you have already begun your homework.
If you have the funds and the bike is available I don't see any reason not to go in that direction.
Sometimes on these forums, it is like it is an all or nothing deal. Worse case scenario, you purchase the bike, you ride the bike, you don't like the bike, you sell the bike. Yes, you take a small financial loss but that's it. Go out buy something else. Not the end of the world. Best case scenario, you like the bike and keep it. Good luck in what ever you decide.