Actually what we have left over after just pulling it from a bin in the garage is a roll of 3/4" narrow insert trim white 25 feet. Which we are pretty sure was not the correct stuff (size) for our Admiral, hence it was misordered and leftover.
But we seem to recall (from several years ago, and we sold it about 5 years ago) that the 3/4" was too narrow and the Admiral had a 1" molding, but don't quote us on that. Please remove some and measure for it greater accuracy.
The insert we used is made by Designer Collection;
https://www.amazon.com/RV-Designer-E.../dp/B003YJI06K
Best of luck!