The POH is a legal document written for every pilot who will ever touch the type. Your checklist is a flying tool written for exactly one pilot: you. When the two conflict, the POH wins on limitations and numbers. On wording and order, you win.
Compress what you already know
The POH says: "Propeller area clear, ignition switch START, mixture advance smoothly when engine fires." You've done that 500 times. Write "Clear prop & start." The sequence is baked in. Spelling it out just gives your eyes more to skim. Same with the runup: "Magneto check" (response: <150 RPM drop) and "Propeller cycle" beat a knob-by-knob script.
Call and response
Write each item as a CALL you can act on, with the RESPONSE as a reference note you rarely need to read. "Oil" is enough to make you look. "7 nominal / 8 for 3+ hrs" is there for the morning you're not sure. The call does the work; the response holds the detail.