There is no reason to feel that a light GA aircraft such as a C152 is inherently weaker than a B737 or B747. You might be surprised to learn that most commercial heavy jets are certificated at only +2.5G/-1G in flaps up condition. A typical GA aircraft is certificated at around twice that level. I have spun the C150 many times. It is not a high G manoeuvre, even if it feels like it, and drastic control inputs are not required for recovery. I went to the Hamble flying college in the 60's when basic training was on Chipmunks. Spinning practise was confined to ex-RAF Chippies which had the anti-spin strakes fitted. These exercises were done dual and solo, without parachutes, with an entry height of 6000ft and minimum recovery by 3000ft. Full and forceful forward stick was required for recovery and it always worked. There was one fatal spin accident in 1966, but that was in an non-straked aircraft.