Spinning Growing Head Illusion Induction

I use to open my mentalism shows with a spinning wheel I am sure some are familiar with. I have shelved it for a while now but thinking of reintroducing it. You spin the spiral wheel for 30 secs and the have the spectators look at your head and it grows lareger. Reverse the spin and your head is seen smaller.

My question is, does anyone think this can cause more than a light trance on some of the audience?
I would like to use this before magic fingers/hands to pick out volunteers.

Thanks.

Candin