Ok, I'll just stick to the facts in this thread so that I don't get confused:
Fact: The mage staff slowly increases your spellcaster's spellpoints, but it has to be equipped to do this.
Fact: The conjurstaff halves the cost of casting spells. It does this without needing to be equipped - it only needs to be held.
So my contribution to the world of BT1 tips is that it is possible for your spellcasters to hold an equipped mage staff at the same time as an unequipped conjurstaff, and as a result he will beneffit from BOTH the sppt increasing AND the half price spellcasting.
This will allow your party to last longer in the dungeons before running out of spellpoints.
(Unless you already use Maven's mage staff party attack trick to increase your spellpoints, this should be a very useful tip.)