According to the TCDS (its been 32 years since I flew one) the min power off RRPM is 90%, but pulling pitch at the bottom of an auto, touching down with 70% would seem reasonable. Stand to be corrected.
A-H, only ever met Bill English on one occasion about '78 or '79. Was spending the weekend with one of his pilots and wife before they headed "North". Bill invited his pilot and wife out to a slap up feed and drinks and finding the pilot had house guests invited us along as well, and picked up the tab for us, which I thought most magnanimous and generous. Know he gave a chap a leg up as well, and gave him a start where others might have not been so generous. Seemed to earn the loyalty of his troops.