We have C1s and the speeds for them are similar to the 172. We teach, 2000 RPM as you enter downwind to slow the airplane to 90 KIAS, abeam the numbers 1500 RPM, flaps to takeoff and pitch for 80 KIAS, 70 KIAS on base, 65 on final with landing flaps, 60 accross the numbers. These seem to work very well. As for useful load, all of ours are equipped exactly the same, and can hold two 200 lb people and full fuel. The still perform much better than a 150 even at full gross on a high density altitude day. Let me know if you have any questions.