Try to find a direction with little-to-no stretch. and make that the direction of your cutout for the bow. Short of that, use 2 pieces, starting at the tips, clamp them down, and stretch as you go towards the handle. Overlap the pieces in the middle, to be covered with your handle wrap.
The stretch will be easy to keep from unstretching once it is all down and saturated with your glue. I like to use a smooth metal tube to help with the stretch/squeezeout of glue.
Mike