It all depends upon the wind...I mainly use a 95%, which works well in the 10kn-20kn range. With wind in the mid-teens up, I switch to an 80% "blade" (flat cut) which works very well. Under 10kn, I have an old 110%, which is too small (and did I mention old), so I am on the lookout for a 135%...
One of the reasons I have 3 jibs is that I hate a partially rolled jib, especially the Genoa. Unless very well cut you get an ugly sail shape, and an even more ugly bunch of sale against the roller which adds windage and spoils airflow (IMHO).
Incidentally, you probably already know this, but the 323 sails very well under jib alone. The few times when I have been out 25kn+, I found her more stable and well behaved - even pointing higher - with my blade, as opposed to a double reefed main.