This is unconventional but I have done many of my own seats this way without issue...... I do not use hog rings, I use zip ties (the ones that are about 1' long not the tinny ones).
Also have a hair dryer handy.
The zip ties allow you to fit the cover with slack, then evenly tighten the ties. They also make attaching the wires to the frame, through the foam, very easy.