Removing an SPF rear clam shell glass window

Anyone ever do? Looking for some input .

My understanding from another builder is they had a glass guy come in with one of those oscillating tools to cut through the adhesive SPF puts it on with from the backside. That stuff is hard like a rock as it is also the same stuff they use to attach the cover of the water pump bump on the firewall. I tried cutting into it and it was impossible.

Call a glass shop to do it. They will have the tools and know how.
I used urethane that one can pull a wire through and avoid vibration and such around any fiberglass.