I've never done it...that sounds wild adding champagne yeast to the secondary.
It really seems kind of overkill, unless you have a stuck ferment (rare in my experience). The yeast won't have any oxygen in the secondary and I doubt they can do much...at least not very fast. Other than really wild, high octane brews, most good liquid yeasts will tear right through it.
Oh don't give me none more of that Old Janx Spirit
No, don't you give me none more of that Old Janx Spirit
For my head will fly, my tongue will lie, my eyes will fry and I may die
Won't you pour me one more of that sinful Old Janx Spirit