Always land with full flap, unless the system has failed. Why else did the designers provide it?
Which UK schools teach '2 notches for a normal landing, 3 for short field'? In any case, there is no 'short field landing' technique in the POH for either the Warrior or Cherokee. You should use the configurations specified in the POH and nothing else. Same goes for approach speed - in a Warrior at any weight and in normal/strong/gusty winds, a closely monitored 63 KIAS is fine, for example. Which is whyt we teach 'point and power' - keep aiming at the touchdown point with the control column and keep correcting the IAS with small positive power changes and the aircraft will be entirely straightforward to land. You shouldn't be flying if the gusts and/or vertical air motions are so severe that you can't control the approach normally.
2 notches, excessive approach speed, balloon and crunch needs to be beaten out of students and renters alike.
As for needing full power to maintain height in a C150 with 40 deg flap on the approach - get the engine checked! I was taught to use 40 deg flap for all landings in the F150 whilst doing my PPL at Cranfield in 1968 - we also practised full flap overhsoots and, whilst the climb performance wasn't brilliant, it was perfectly manageable.