Finally found a thread with sway bar sizes:
https://www.camaro5.com/forums/showthread.php?t=335976
Perhaps a front SS bar (FE4) and rear 1LE/ZL1 bar would be a good start. I believe the Pedders are 8kg front and 10kg rear if I'm not mistaken; compared to factory ZL1 springs (cause you're running ZL1 wheels/tire specs) your front is a fair bit stiffer than rear compared to a factory ZL1, so it makes sense to go with a smaller front bar (assuming you consider a factory ZL1 to be a good reference point - I'm sure those engineers know what they're doing!).
I'd actually like to loosen things up a bit too and see the difference (on BC Racing coilovers which are 8kg/12kg, so pretty stiff), but I have the V6 and the rear brakes get in the way of any bar except the JPSS and maybe Hotchkis bars. Maybe I just need bigger brakes...
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Overkill/Self Tuned; Mace Camshafts; K&N Typhoon Cold Air Intake; Ported 80mm Throttle Body/Intake Manifolds/Manifold Spacer; Solo Performance High-Flow Cats, Cat-back Exhaust; Vitesse Motorsports Throttle Controller; Elite Engineering E2 Catch Can; BC Racing BR Coilovers; JPSS Delrin Radius Rod Bushing Inserts, Sway Bars; Pegasus Aluminum Rear Cradle Bushings, Camber/Caster Plates; Z/28 Toe Links, Trailing Arms, Upper Control Arm Bushings, Rear Shock Mounts