I'm not quite in the Kiton class yet. I do have some nice suits in 120's that I really like(Canali, Samuelsohn). But at my wife's law firm many of the partners, where price is not a consideration, wear top of the line suits in 180's(Kiton, MTM, Bespoke, Brioni etc.)
Many have them have told me that they wished they had gotten 150's and they felt the 180 fabric was an unneeded affectation.
I'm certainly no expert and I don't even know if Kiton offers 150's, but perhaps some members might comment on the desirability of 180's versus 150's and their experiences.
Regards and Good Luck!