Re: How do I go about doing this?
Don't cut the gasket!
Mine is a BlueBird. The OUTER side of the gasket has a spline in it. Find where the spline meets. Start there. I found a paint key like what you open paint cans (and beer/soda bottles) with worked great to start pulling the spline out with use the hooked end you normally use to open a can lid). Wet and soapy makes the job easier. Once the center spline is out, we very carefully pushed the gasket & glass INSIDE using the hooked end of the paint key & some wooden craft/popscicle sticks to flip the outside thin edges of gasket onto the glass and past the metal body sheet metal, This is a two person job (one inside/one outside) if you can get someone to help. Once out, wash the gasket in laundry detergent with a little bleach added to kill any mildew that may be on the gasket.