M-Atk Up vs Swiftspell vs Half MP

Looking to build a few mages, and wondering how y’all put these Support abilities to use.
Magick Attack Up could help a caster that’s trying to blitz constantly with fast damage spells, think the -aras. But when it comes to maximizing the DPS of the bigger spells, I imagine Swiftspell helps a mage land them more consistently whereas Half MP doesn’t really check any boxes for me at first glance. Happy to hear suggestions/builds.