Quote Originally Posted by Supersun View Post
You need it on at the start of the cast for the reduced casting time. You still need it for the completion of the spell if you need the reduced recast (which you should probably be wearing haste gear for anyway).
I use Haste + Fast Cast gear to help with Utsusemi recasts on THF and PUP and with Utsusemi and other magic recasts on PLD. I'm not a red mage, but I just had an idea and wanted to see what a wider group beyond my immediate in game friends, thought about it.

Which brings me to 1 other idea I had based off Celes' ability in FF VI - Runic Blade. Basically give it a 10 minute recast, but with a sword drawn, the RDM can force an offensive spell cast by an enemy to be drawn into their sword and the RDM can recover some MP from it. It can either be the full amount of MP used to cast the spell, or a percentage of it.