Heroic TF Invocation of The Dawn vs. 522 1h + shield ?

[Freia]

This is probably gonna blow some people's minds here, but I haven't seen anyone mention that the 2h STRONGLY favors Glyph of the Battle Healer.

Holy paladin autoattacks are never going to favor that glyph.

[Calimon-ZJ]

The 2h will also lower your mana regen while you melee the boss since you swing slower than w/ a 1h I would think.
Your best bet is to have a macro to swap to the 2h on heavy damage portions of fights for a boost in output (meg rampages, quills, etc...) but keep in mind that will take a global.