I just did mine and it went much better than I had feared. I used the window glass (removed of course) to bend the channel around. This worked fine and the fit in the frame was great.
My vehicle had stainless holders for the ends (screwed in to the door), I measured with the channels dry-fitted in the frame, then used adhesive to glue the stainless holders to the ends.
After the ends cured, I put adhesive on the window frame where the channel would fit and put the channels in place.
I used masking tape to hold the channel in place while the adhesive cured.
