I’m not really an expert on Strat pups, but I’ve done a lot of swapping and listening. I honestly don’t think most people would be able to pass a blindfold test. In general, I think people would be able to say they either like a certain style or not. True 54/Early 55 Strat pups should be A3 mags, it then changed to A5. I’m not sure off all the particulars through the years, different staggers and wire type, etc. I personally like flat pole pups. I think we as players get very obsessive over tiny details. I have found Strat pups to be responsive to height adjustments, and then factor in how they’ve aged. So, short answer: I’ve found A3 to have a little more sparkle to the top end and a softer low end. They seem to “bloom” to my ears. A5 is “snappier” and more scooped in the mids. Different DC resistances will kinda change the output, to a certain degree, but I hear it more changing the EQ curve more, which does change the perceived output because it’s hitting the amp different. I don’t think understand that. I’ll have to think more about this topic.

My personal favorites are A3 early 54 type, they have a sweetness and chime that I like. I also usually like early to mid 70’s flat poles, they have a certain “muscle” to the sound. It’s hard to explain, but I like them better than the 62-65 types.