Helper springs location (top or bottom) and related rattle

Curious what's the best way to place helper springs on coilovers - on the top of the main spring or at the bottom?

Currently I have mine on the top and do get some annoying rattle going over small bumps.

Setup is 981 Cayman with Ohlins R&T, DIY. This is the rear strut.

Thanks!

I figure at the top, so when it's compressed it's sprung rather than unsprung mass, and in the extended position it doesn't have the gravitational load of the main spring on it so it's less likely to rattle - still got inertial loadings, though.