On my first one after 15 minutes of paddling I would get dizzy.
So after a year of oxygen deprivation I took a deep breath and cut the gasket.
Don't place a hard surface under it when you do the deed as the blade might 'turn' - I used a block of wood and a new razor blade. Don't cut a jagged line - needs to be smooth and continuous. Little nicks turn into big tears
The Connyak BBS