If you have difficulties pressing the glass into the channel with the glazing strip wrapped around the glass edge, it may be because the rubber is too thick or stiff. Example, replacing the rubber seal on the bottom of my windscreen, I found the rubber too stiff and it didn't seem to fit the channel very well. I purchased the same item from another vendor to find the rubber was softer and the fit was designed better.
Some of the items we get aren't made as well as the originals were, so it comes down to who the vendors gets their parts from. The forum guys seem to know what vendors sell the good stuff for a specific part. Vendor A has the good X part, where vendor B's same part is of lower quality and frustration is built in trying to install it.
Using a lubrication product may help, but as pointed out, which one?
Has anyone tried using a hairdryer or heat gun to soften the glazing strip?
You might bring the glass/frame/rubber to an auto glass shop. They may have special tools or glazing material that will fit better.
Good luck