Is there a trick for installing a Tinnerman spring nut?

Folks -

I know that if I get someone to sit inside and hold the flat Tinnerman
fastener, I can screw in a machine screw from beneath the a/c. This is
not the type of fasterner that clips on to the edge of the metal.
For one person trying to either install or remove a screw from the
afore mentioned fastener, is there a trick for holding it in place? -
Mike