I'm in the preliminary stages of planning a small cessna dropzone primarily catering to tandems. The proposed dz field elevation is 5700' , average summer high temperature of 85 degrees. I would like to run 2 tandems to a minimum of 9000' AGL, ideally I would like to get to 10500' AGL (16200 MSL). Any lower and I feel like I would be cheating the students. I would also want to be able attain 35 to 40 minute turns. I understand that a stock 182 would have zero chance of attaining this altitude in a timely manner, if at all.
I'm looking at keeping my costs down, so a turbine 206 is out of the question. I prefer to avoid a turbo 182 if at all possible. I've heard about reliability issues with them, and upkeep seems to be much more expensive. If I'm wrong about this please let me know.
I prefer to go with a straight tail 182 with either a 275, 285 or 300 hp conversion. In your experience, would this be adequate for my performance criteria? What specific airframe upgrades would improve the climb rate? I've heard mixed reviews about the different STOL kits. The runway is 7000ft long, so takeoff performance isn't as important as climb rate.
I'm sure I'll have plenty of other questions as I continue planning, and thanks for the help.