Hi!
I used some oils with smaller than 32cSt for my 2015 350 but the best feeling I had was with the Amsoil #10 with exactly 32 cSt as the oem TELLUS has. Also the Nils 10W with 35 cSt was really close to what I wanted if not the same, but it was during the warmest month of this year, August. Always the air gap was at 110mm. I will experiment more with air gaps (more than 110mm) in my 2016 300 2T and with probably a bit lighter oils than 32cSt. But at least I know from the 2015 which oils for sure work well (Amsoil #10, and Bel Ray 10W should work the same as it is also a 32cSt rating...).
Leon