I do 2 for solo riding and when I bring my wife along (195 for me, 120 for her). It seems to be fine.
That's good to know 2 seems to work for both. I took my daughter out a couple days ago and 1 did seem too soft...it felt heavy and a bit draggy. Guess I'm just too lazy to have to have worry about always changing it. I'll give 2 a shot for both.