I have a similar situation. I have a 96 Standard with the unchambered body.
In around 9.5lbs. It is absolutley stock with the 490/498 pickup set.
I also have a Goldtop Classic chambered body at about 7.5 lbs with BB1,BB2s.
I really love the tone from the 96, it is almost "Buttery", but can get some raunchy treble tones as well.
The GT has a crisper, cleaner tone but can be dialed in for more mellow tones without sounding "muddy".
As Jimi said, you can really feel the difference after a playing session. I don't gig but I will usually play for an hour or so at a time standing up.
With the lighter chambered body I feel no fatigue.
I am really amazed at how good those stock pickups in the Standard sound.
So I am sure it is the heavier body that contributes to it. I had a 2008 Studio with the same pickups, in a chambered body and it sounded much crisper, but in a good way.
I do give the Standard a slight edge in tone but the weight issue "sinks" it.
Overall the chambered Les Pauls fill all of the boxes on my PERT chart so they are the winners.
The Blues is alright!
Guitars: 1968 Gibson SG, 2005 Gibson SG Standard, 2006 Gibson LP Classic Gold top, 2004 Epiphone Elitist LP Custom, 1996 Gibson Les Paul Standard. 2001 Epiphone Sheraton II, 2007 Epiphone G400.
Fender Strats: 1996 Fender 68 Reissue CIJ, 2008 Squier CV 50s, 2009 Squier CV 50s Tele Butterescotch Blonde
Amps: Blues Junior Special edition Jensen in Brown Tolex with Wheat front, 65 Deluxe Reverb reissue,1970 Sonax reverb by Traynor, Avatar Custom 2/12 Cabinet with Eminence Legend V1216 speakers,
2008 DSL100 Marshall Amp , Fender Super Champ XD,Fender Vibro Champ XD
Effects and Pedals: Fulltone Fulldrive II, Fulltone OCD, Fulltone Mini Deja Vibe, Fulltone Fat Boost, Dunlop Crybaby Wah, Boss DS1, Boss DD20 Giga Delay, Boss TU2 tuner, Boss BD2, Ibanez TS9 Tube screamer, Zoom 505. Radial tonebone hot british.