here's a shot of the 10,8 quest left ,11'nalu right.don't know if this will shed any light on your decision ,but the 10,8 has less rocker ,it paddles faster than the 11'...yes maybe a little tippier being 30 instead of 31 .most people i have given a go on the 11'have had no issues .the 15 litres extra and 1 ' wider make it more stable ...
i sold the 11' because i wanted the smaller board ,and loved the polynesian designs underneath....i did wish it came as a thruster like the 11 nalu ..but it was a good price ..i have had a few goes on the 11,2 quest ..its big .and easy .i surf everything so didn't appeal to me ,but it was very good in the rough, and had good speed ..don't forget the 11,4 nalu ..its still a great board ..it was everybody's favourite at one stage .

my daughter has one ..no bodies aloud to touch it .
the choice is yours echidna66...they are all good