When I gave complex endorsements in a college flight program, I never signed anyone off with less than 6 hours flight time with a minimum of 30 takeoffs and landings.
The average transitioning pilot in those cases was coming in to the Arrow with all Cessna 152 time up to that point in their training. So there are a lot of differences to go over in those cases...high wing/low wing, twice as much power, fuel injected engine, different fuel system, retractable gear, much higher gross weight, an extra 40 knots of cruise speed, etc.
Usually we'd do about 3 hours of air work with about 3 hours of touch and goes. Then, since our insurance required them to have 8 hours before flying solo, I'd usually take a cross country, do some night landings, shoot some approaches, or something like that with them to get them the 2 more hours they'd need to solo...and honestly, those two hours were never wasted burning holes in the sky.
Remember, it takes the average person 8 times of doing a task *correctly* to learn it for good. Otherwise they don't retain it very well. Extending the gear is not something that can be messed up on even once. Before signing anyone off, they had to do at least 10 landings in a row without me having to remind them of anything related to the gear.
I can't imagine a person having a very deep understanding of constant speed props, emergency procedures, normal procedures, etc. after only one or two flights, unless they were coming from a similar airframe (Cherokee Dakota to an Arrow, or 182 to 182RG for example).