We replaced the leather tack strips inside the metal bows/irons themselves with very thin-cut strips of pine (or any other flexible wood would probably work) when we did our '29 phaeton years ago. Steaming these strips, or possibly even soaking them in water to make them more pliable might also prove helpful when relining the interior portions of the irons. There may be other, more current solutions now than were available years ago when my father and I re-did ours. However, the top has been in place (and is still firmly attached) for 55 years now, and is still doing well (although the sides have shrunk up some over the years since). I hope that this may prove helpful to you. Good luck going forward.