Defrost heater duct

[Cold Blue]

I have the original defrost ducting on my 48 - but it fits poorly. Won't stay on the metal windshield defusers or the heater - keeps slowly working its way off. Just put a hose clamp around them to get a tight fit? I think the duct was originally a press fit, but the years have taken it's toll on it, kinda like me...Ya'll got a better solution?  Duct tape?? LOL... Thanks!!

[Adam H P15 D30]

I use large cable ties when I install Vintage Air systems.  Tape always seems to come off and a worm clamp might be hard to access??