I've done 3.

I always order the complete gasket kit from a Moparts sponsor. Always fits.

I always order the cores from Rockauto.

I always have a hand vacuum pump and I check operation of all doors after the rbuild to make sure no glue/gaskets inhibit movement.

Not hard.

No matter how responsible he may seem, never give your gun to a monkey!
1970 Coronet Vert
1972 Charger
1974 Satellite Sebring Plus Sundance
2001 Ram 4x4
2002 Intrepid
2006 300C