I simply sandwiched them between two layers of burlap with spray adhesive. Seemed to work great. Simple, and I don’t think they’ll move over time, but we’ll see. I agree... they seem to provide significant support... good spring steel.
I see you had the interwoven wires and they looked pretty decent. Did you weave them back in? It does appear that you did. They make a huge difference in the feel of the seat.