Funny, after spending the last 3 weeks determining how I should deal with same issue, I JUST ordered what I decided to go with for my 2008 19H this morning.
The original seal was 9/16 wide and 3/4" tall, (0502453 - SEAL,BULB D 9/16X3/4 WHITE ***NO LONGER AVAILABLE***)
you are correct, you would never know it used to be 3/4" tall anymore.
I did not have any luck finding exactly that size.
The original part number, along with any of the other Jayco "replacements" found on Google searches, also did not come up at being available. (I did speak with Jayco parts as well, they had nothing else to offer, we are on our own on this repair)
I found a number of posts suggesting to "add" a seal onto the door edge as well, so what I decided to order was a EPDM Rubber seal that was just about 9/16 wide, and about 1/2" tall, then added a flat/ribbed seal onto the door that is just over 3/16" tall.
my thought is both seals will work together to close up the gap.
what I ordered:
for the D-Seal,
https://www.amazon.com/dp/B07GVCGHXC...t_details&th=1
and then I paid more for the flat seal as I wanted a similar EPDM Rubber product, Amazon did not show many options, and frankly I had wasted way too much time on this issue and just needed to get it ordered. I also decided on this specific product due to the ribs, thinking it will help seal against the D-Seal.
https://www.amazon.com/dp/B087G58DSJ...roduct_details
I am hoping this will resolve my ability to see daylight thru the old rotting out seals, while I await the tents being returned from having new J-Lock sewn into them
I am working to resolve the typical cracked-J-Lock and leaking water into the camper due to the screws used to affix the tents. (will NOT be reinstalling the screws)
Hoping to get this installed in the coming weeks, just in time to put the camper to bed in the barn for another winter.
hope this helps, I spent too much time on this issue. Happy to provide more detail if you have added questions, love the 19H, great size unit, have done a lot to it.
Steve,