Regency R14 gasket size

[MAD MARK]

Have an older Regency R14 insert. I believe the gasket is too large and it needs changed out anyways (sagging).

Anyone know the size?

And is there anything better than the Rutland Gasket in a tube? Having marginal luck with it.

 

[DAKSY]

3/4" or 7/8" will work.
Use RTV silicone to adhere it to the door.

 

[MAD MARK]

So this is good then? Pic below. #1.

Seems like the gasket stuff turns really hard and un-adheres from the gasket. #2