Well, if you are doing this with a party it isn't too hard to get back your kensai powers once you dual... Heres what I remember doing.
I horded all the scrolls I could find, had all my party members leave me, and did some serious scribing. Afterwards I brought them all back... It nets you alot of easy expirence, and should get you several levels into your magedum. After that you can just pretty much hide behind your party members until you regain kensai-ness.
If you are soloing it becomes tricky... I lost interest after a while, but I did get a good ways into the game before I quit. I went around gathering scrolls and such before I dualed, and afterwards did easy quests such as the circus, and slavers. It actually goes pretty darn quickly if you are all by yourself, but be prepaired to dance around with a sling for quite a while in some fights
Good Luck.