|I've got a couple thousand hours now behind and beside R985's and a slew of other piston engines...doesn't make me an expert however.. Just an observer.
I know exactly who you were flying with that was whacking the power to idle once they were at a lake shoreline. I remember the justification he gave me for it too and I still refused to do it. Needless to say, he goes through a lot of cylinders. But, when you're paying the bills, do whatever you want.
I'm sure you're aware that Radials and most piston engines like smooth applications and reductions in power. No big temps spikes or drops. Never drive the thing with the prop(more of a concern with the 1340)... Don't make the prop governor try and play catch up. Make sure you're in the green and warmed up properly before a takeoff (this was a big one, watched a couple rookies pop oil coolers and seals). These simple things will keep cylinders AND the person footing the overhaul bill happy. The quasi SOP we used on the coast was full rated takeoff, and as you broke water come back to 33/2200. Climb out after obstacles at 30/2000 and cruise at 28/1800, although occasionally a 'hot' cruise power of 29/19 in a couple of the machines that needed the extra I haven't spun a 985 in anger in just about a year now though...
Ohh and edited to add, we never leaned. Legs were too short to make a difference and on 87 it didn't much care for it.