Re: DiMarzio equivalent to Quarter Pound?
If you want a beefy tone that is still single coil....
Have you thought about upgrading the Legacy's alnicos for the S-500's MFD singles? Drop-in replacements. They are a powerful pickup with a full-range response.
And...how are you adjusting your PTB controls? I set the TREBLE on 10, BASS on 5. Then I set my amp for the twang I want from the bridge. If I want a fatter tone, I can back down the TREBLE, and add BASS.
The original Legacys used Duncan SSL-2s with flattops. The flats work well with the standard 12" radius board. The G&L CLF-100 pickup of the newer Legacys are virtually the same. The stock Alnicos give you that great vintage strat tone, but the MFDs of the S-500 are just bigger...think Texas blues or singing sustained fusion tones.
I have Legacys, Comanches, S-500s and Legacy Specials; all are good. Z-Coils sound very close to the S-500 MFDs, but are hum-cancelling. The Legacy Special's Gotoh Blades have more of a thick, PAF-ish tone. I usually gig with a Legacy and a Special. But if I can only take one guitar, then it's usually the Comanche or an S-500.
One other set that I really like is the Texas Hot Antiquitys. I have sets in two of my ash Legacys (I have 18 G&Ls), and use the RW/RP middle and the Power Bridge. Another flavor from the others; not as bright as Alnicos and the MFDs, brighter than the Gotohs. Beefier. Creamier, smoky mids. Almost remind me of P-90s at times. For Nile Rodgers' rhythm parts with Chic, I'd want the stock Legacy. For something more ROCK, the TH Ants work great. Bridge pickup has balls. A great set. Not giving up my stock pickups, but I like the Texas Hots for a change of pace.
I hope this helps.
Bill