I'm just looking for some help on this.
Wiki says that conserve mp gear can take effect at pre-cast time and be swapped out mid-cast and still take effect.
The way I see it, if there are no alternatives to enhance the spell conserve mp gear should be put in pre-cast and then switch to more appropriate gear.
I've been digging through several different research items and I can't find anything to support this. All of the research says about the tiers of conserve mp, how often it works but there's nothing to support the claim that conserve mp gear can be removed mid cast.
Wiki Conserve MP link
Wiki source (alla)
SCH research on Conserve MP