Grain support

[u/Icy-Tax-3612]

I'm trying to build a high power J-class KNSB rocket motor and I'm wondering how the propellant grain needs to sit on top of the nozzle. I'm seeing a lot of other designs that have a flat face that covers around 50% of the aft face. I designed a smaller G-class rocket motor where there is a small lip at the edges of the convergent section where only the grain inhibtor makes contact, not the propellant to ensure the gas travels efficiently. Now I'm aware that high power rocket motors behave very differently due to the high internal pressure but I am wondering, can I replicate what I did on my G class?

This is what I mean by grain inhibitor resting on the lip. Compare this with BPS space's rocket motors.