[Miller]

it would only be 3 turns of of duration really with 1+1 per 2 charges

The first one is true yes, it's an extra turn on powerful buffs and free holy aura regardless.

As for everything else:
As I said earlier, using Blazing Sol with only 1-3 charges isn't pointless because it locks your Solcharges in place, which means it can be a valuable set up tool that saves you a lot of momentum if you don't mind the FP cost and the following cooldown.