I made eight stringers to go between the firewall and the front top rib. I drilled the holes in the firewall mounting channel, four each side, with the aid of a jig I made. I may not need all of the stringers ( GTX35R is to be riveted to the bottom of the front top rib, right hand side ) so I will cleco them into position for the time being. If I do require the stringers in the future it will be easy to rivet them into position to support the electrical wiring.