Yeah, seems to be a very personal thing.
I am using a 9m R1V2 as my light wind weapon.
Same weight as you.
It does not really happen to me that anyone is foiling when I can't.
If I would pick a Chrono UL for light winds it would be the 11m.
I prefer to be precise and active flying the kite and riding the foil, instead of being pulled by a massive tractor kite.
My most used kites are both 6m, R1 and Enduro.
Personal preference. Good for me, may be completely different for others.