Topband: Vertical radials

[AD5VJ Bob]

Does anyone know if using a rectangular long metal plates starting at the base of a vertical and extending out along the ground
would be better than say 12 or 15 wires for use as radials? And could the plate be shorter and still be more effective for a radial.

I tried modeling this on 4NEC2 but cant seem to figure out how to model a ground system with the antenna. It just gives me choices
of generic ground conductance measurements for ground. 

Which is not going to tell me what I am trying to find out.

Tnx
Bob AD5VJ