I’ve got a ’52 RI and I have some thoughts: I refinished mine because, in a spectacular display of not getting the point, Fender put a thick poly undercoat under the thin lacquer coat, which conventional wisdom would say is a resonance killer. So, personally I would steer clear of any Polyurethane products like Varathane. I’ve had the original pickups in mine, had them rewound to Broadcaster specs, replaced them with O.C. Duff pickups and then replaced the neck PU with an LSL. In all that the guitar never sounded dull. So I doubt if it’s the pickups. Also if you want traditional Tele sound you might want to use a traditional Fender bridge assembly, after all they say that strats just don’t sound right without the thin steel saddles. One last thing, does your bridge pickup have the copper plated steel support plate on the bottom? That has a lot to do with the sound.