2 Completely Different Issues. Selecting coils for preferred ride ht. is distinct from diagnosing uneven riding level side-to-side.
Coil selection on its own is quite subjective but you'll get plenty of suggestions from other's experimentation I bet.
Shocks have nothing to do with ride ht. The only exception is for gas-charged shocks, and then only for a month or so until they relax a bit.
For correcting uneven tilt you can search:
"Mis-punched rear control arm mount hole during original frame production" (there's a TSB on it I think)
"Bent - twisted front or rear stab bar(s)" (personal experience)
"Collision damaged A-arm" (personal experience)
"Seized shock" (on an old Camaro once)
"Decayed/rotted body bushings"
"Incorrect front coil orientation or not seated correctly in perch" (not applicable if you've never replaced anything yet)
"Deferentially sacked out old coil" (potentially your case if all still OEM)
\'96SS SOB: SSRI, Herter Tune, Tri-Y II, , 3000 Edge, F/HO bars, METCO extendeds with CV MMC, Bilsteins, currently Vredestein Ultrac Sessanta (315/35 rear). Finally, wait for it... LT-4 knock module!
\'96FWB BUW-Butt Ugly White: PCMPerformance tune, HDFA w/ swissed filter, 1/2 SLP s.s. catback with H- and Flow Super 50s, oem opti rebuilt 3 times, SS Bars, METCO LCA, Airlift 1000, Monroe SS, PowerTrax No-Slip, CTS wheels with +1 rubber. Finally, yes again... LT-4 knock module!