windlace -
door opening weatherstripDo you have the channel retainers (grooved retainers) or the screw-in retainers? Most likely you have channel/grooved retainers? No screws were used. If you are going to screw them in - the choice of size is whatever works and looks right to you.
If someone posts a reply who used screws in the channel/grooved retainers, please post links to photos.