Just picked up a Gretsch Streamliner Jr for $$. Better workmanship than the 6120 I sold recently. Only problem is the pickups are "dull" sounding. I raised the pickup height and that helped. Any recommendations on replacement pickups that are direct replacements(no modifications required)? I play through a Supro Titan amp. I also want to replace the controls with speed knobs or Gretsch logo chrome knobs, how do I remove the current plastic knobs?