Sadly you have to go by the manufacturer's descriptions. You'll see that DiMarzio class their pickups as vintage, medium or high powered and also give you the millivolt output (which they test by setting them to the same height and pluck the G string with a medium pick - inaccurate, but gives you a good general idea). Seymour class them as either hot or moderate, but further than that you have to try them ☹
Quite honestly, choosing pickups is a minefield as there are no standards between brands - I still make "mistakes". Opinions from users are one thing, but most of us tend to lean to one brand or another and have a very subjective opinion of what constitutes good tone.
themanthatwalks wrote:
What are the diffs between weak and hot pickups except output volume?
Sorry missed this before somehow. Generally what happens is that the hotter you wind a pickup the more midrange it gets and the less high frequencies. It also starts compressing the dynamics the hotter it is. Neither is bad. The extra mids of a hot pickup give you more of the frequencies you need for a "lead" or "solo" guitar and the extra compression helps a little to cut through too. Often ceramic magnets will be used, which not only are more powerful, but add some top end back - but it tends to be a bit harsh and brittle, which affects clean sounds adversely.
Lower output will be more dynamic with more of a midrange scoop ideal for a rhythm that sits behind a lead voice or instrument. The extra sparkle on the top end helps it cut through without being harsh and it will have the most nuance and detail. Usually in this setup you will use an overdrive (or sometimes an amp) that has more of a midrange push to get more of a lead voice (best of both worlds, IMO).