Is there an alternative method to hold the rear windows in contact with the turtleback outer skin during cure ?
If you cannot manage the Cleco’s, another solution is to clamp a 2″ x 4″ the full length of the turtleback, then insert soft foam wedges between the 2″ x 4″ and windows. Be aware that the windows do not always have the same curvature as the turtleback, so you can expect some minor flox filling. If this is unacceptable, you can shape the windows to the exact curvature by heating them in your kitchen oven to about 150-270 deg F until soft.