I want to do a leak-down test on one of the cylinder that has a 30-psi. How much pressure should I pump in the cylinder.

Is this the metod

bring piston up to tdc on compression stroke and then compress the sick piston and then listen, if air comes out of crank case then the rings are shot, if air comes out of exhaust then the exhaust valve is shot, if air comes out of the intake then the intake valve is shot. I hope I can rent a compressor or can I use a propane tank as a pressure device.