I purchase most of my supplies from Aircraft Spruce https://www.aircraftspruce.com/catalog/appages/siliconecowlseals.php
This is what I used: The fiberglass insert is really fiberglass woven material laminated into the silicone for added durability. I worried a little bit about this as water can wick into the cut edge but so far not a problem. It also comes without the fiberglass and it would probably be ok as well. I will be aboard in about 5 days and I will see if I can track down my dimensioned drawing of the wedge I had cut from teak.
Silicone 1/8 " x 3 " x width of the door seal. PN 05-00771-3 $5.35/ft.
Gary S. Silver
Amel SM 2000 #335