Tudor front sets

[Gold Digger]

I have a 1930 Tudor with the original seats. On a long drive I notice that I'm sort of fighting a battle to stay in the center of things with the original coil springs in the seats. Is this something anyone else has encountered and if so what's the cure. I'm not so concerned about the passenger seat but have kicked around the thought of putting zig-zag springs in but would like to here if someone else has ever tried this or is there something better.