The 3 nubs are asymmetric and the flywheel only fits one way, that is intentional. They only align, they do not provide real driving force to the flywheel or they will slip. If it feels like it won't seat fully on them, rotate it until they all line up.
115 PSI is fine, well above minimum spec. The Hobbit engine stock is fairly low compression ratio. As mentioned once the rings seat pressure will increase some.