I'm designing a trap door with a gas spring design.  In the closed position the gas spring acts to keep the door closed when I want to open the door I have to put some force on the red nob handle to toggle the gas spring to over center it then the gas spring acts to help open the door.

I'm trying to verify my hand calcs to specify the gas spring.

I'm a nubi when it comes to simulation.

Appreciate any suggestions, file attached.