I would stay away from the day planner holster idea... as a woman, I'm finding it hard to carry concealed while still being able to wear fashionable clothing, or simply carrying in warmer weather while I dont look like the freaking Michelin woman! Thus, I'm forced to carry in my purse a great deal of the time (although I do LOVE my Super Tuck holster!). I cant tell you how annoying this is for me. Not only is it a pain in the rear end to try and keep someone from seeing the @@@@ thing while I get my wallet out, etc. But I cant set my purse down for one second just on the off chance that someone swipes it, etc. Think about having to hold that day planner 100% of the time. I'd try to find a nice pocket holster or some other holster that will work for you.
Just my two cents,
Moosie