Hey I know these are both low output but was wondering the characteristics of both...
which ones have the best bell tone? I want pickups that are punchy and bluesy, but not too piercing. How do these relate to the texas specials?

That's really tough to answer. You're best bet is to find a guitar loaded with each of those. You might find some videos on youtube that allow you to hear the difference...

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I've had Fat 50s in my Strat for about a year now and really like them. They have a nice full tone and more bass as opposed to the heavy mid-range like the Texas Specials.
As far as the 57/62s, they have a great tone but I don't think they have quite as much bass as the Fat 50s. They also don't have a RW/RP middle pickup. Not sure how important that is for you.
If you want a more "classic" sounding setup, I would recommend the 57/62s. If you want a little more punch, go with the Fat 50s.
I would look at some local shops and try out some guitars with the pickups already installed. The sound on youtube isn't always that great and it depends on the amp, etc.

Good luck