Bondo'd a piece of 1/4" wood shim stock to font of cowl to set the separation from the spinner backplate. Wrestled the aft face and sanded here and there to achieve a good fit to the supporting flange. Ensured nose flange was symetrical, then sunk 4 clecos into the aft flange. I predrilled the flange holes, then using a light under the cowl, could see the holes and drill into them.