The Q version 3 x 26" is what you want.
I have a Q1, Q2, Q3 in the Garage (err basement, it's winter).
I can confirm the that a 700cx23 will not fit on the Q1 (front and back), Q2 (front no, (back almost)) nor the Q3 x 20" (front)
The Q3 x 26" version will fit a 700cx23 both front and...