[Try to finish with the prop pulled back against compression so the starter motor has less initial resistance (do not turn engine opposite to usual direction as this can knacker the vac pump vanes).]
Sorry - this thing about not turning the engine backwards by hand is a popular misconception. I have an e-mail from Parker Hannefin's Service Dept which states that it will cause no harm whatsoever. What will ruin the vacuum pump carbon vanes is oil/solvent contamination or fitting the wrong handed item to the engine and running it (some pumps are designed to run CW, others CCW).