'35 door top weatherstrip installation

[rich b]

Tried to install the door top weatherstrip on my '35 3W yesterday. I lubed the strip and channel with straight dish soap; but was only able to get it pulled in
about a 1/3 of the way before it stopped. I also tried sticking the outer edge in and then tucking the inner edge in; but that does not work.

The channel is smooth and clean as well as straight.

What is the secret to getting the strip installed in the channel?

The rubber strip is from Bob Drake.