Don't just lube the channel part. When it comes to the flap that will go past the dash, put a little lube there.
In another lifetime, when I was an electrician's helper, one of the first things I was taught on a circuit run was that, if I was on one end pushing the wire in to the conduit, while the other guy was pulling the fish, the job would be so much easier than one guy just pulling the fish.
As you are pulling one one end, push the rubber in on the other end. You might be twisting your body a little while you're reaching in the door opening, But pushing definitely helps. If it gets stuck, stop, find out why, address and continue. If you gave to remove to start over, do that!
Always keep in your mind that, if some guy or two in the factory could install this rubber all day long, you can certainly do this one off job. That factory guy wasn't born knowing how to do this. The only thing he has on you is that, he got better and faster by doing it all day long, day after day, job after job.
