Can you use Form of the Dragon + Righteous Might AND Legendary Proportions to stack?

[BlueWitch]

Say you're a high level Mystic Theurge.

You get to cast one Divine Spell and one Arcane in one turn.
And before this you use a Quickened Spell of one of these.

Will the Size Increasing Effects Stack?
Potentially making you a Colossal Size Dragon?

(Yes, I know this is impractical, but still, I think it'd be lit! XD)

[Jack_Simth]

Righteous Might includes the line "Magical effects that increase size do not stack."

Edit:
Neither Form of the Dragon nor Legendary Proportions do, however, so those two should stack with each other (although the stat bonuses won't, as they're all named as Size bonuses). One step shy of colossal.

[BlueWitch]

Righteous Might includes the line "Magical effects that increase size do not stack."

Edit:
Neither Form of the Dragon nor Legendary Proportions do, however, so those two should stack with each other (although the stat bonuses won't, as they're all named as Size bonuses). One step shy of colossal.

Thank you for answering!

[Kurald Galain]

Righteous Might includes the line "Magical effects that increase size do not stack."
And as it turns out (https://paizo.com/paizo/faq/v5748nruor1fm#v5748eaic9t5u), this is not a specific rule for RM, but reminder text of a general rule that size increases do not stack.