I've started prepping my door, and will be putting furring strips and insulation on the door. Now I come to the problem of the door handle. I'd like to be able to put the door knob on top of the furring strips and fabric, but can't find a door knob that will do wide enough. My solid core door has another layer of 1/2 plywood GG'd to it, and then i'll be putting 1-1/2" furring strips on top of that, so 3-3/4" thick total. Any one with really thick doors have a solution?