If the pickups are
too close, the magnets will damp the vibration of the strings, reducing your sustain dramatically. It may also pull the strings toward the pickups in a way that makes it impossible to set up the intonation properly.
As a basic 'starting point' setup, fret the high
E string at the highest note, and adjust the bridge pickup to sit about 1/16" (1.5 mm) under the string. Then fret the low
E string at the highest fret and adjust the bridge pickup to sit about 3/32" (2 mm) below the string. Adjust the rest of yor pickups to be a little further away from the strings, as
SLY has described. If you have a 3-screw or 4-screw adjustment, make the face of the pickups parallel with the strings.
If you have new-style, 'hot' humbuckers, you may find that this is a little too close for comfort, and you'll need to back everything away from the strings a little bit. I'm not sure how much pull you can expect from a new set of Synchromatics. You'll need to experiment with them to find out what settings work best.
BTW: A
Gretsch!! {drool} :D
Lordathestrings
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