Hi David,,
Your planing experience is very different from mine. On a short trick water ski, to slide the ski across the water sideways is much more drag than to plane with the ski parallel to the direction of motion. I used to water ski alot. Back in the old days, 1950's, when a 60 horsepower Gray Marine inboard engine was a big engine, the boats planed and they were long and slender, skinney boats. Look at old Christ Craft and Correct Craft power boats. They were all long and skinney because they had so little power to work with and they wanted to get the most speed out of their boats with limited horsepower.
As far as foils go, I'm glad to let Sam Bradfield fight that battle. He is a long way down the road from the rest of us and the trip isn't over yet. You don't see foil boats zipping around on 'real water'. They run good in flat water and strong winds but I don't know where to find that condition except in that ditch full of water over there in France.
Be careful of rhumors from guys in SA. A sailboat will always plane on its mid hull section out to its bow. The thrust from the sails is up in the air/rig at the CE and this creates a downward pitching torque which forces the boat to plane on its forward sections, like a seaplane. On a power boat the thrust is down in the water at the propellor. The thrust being generated in the water below the hull creats an upward pitching torque which lifts the bow and makes the boat plane on the aft sections of the hull.
Bill