Wheels & Tires - Ace Alloy Slicks?...offsets???

So, I have been noticing an increase in traffic on here regarding these ACE ALLOY "Slick/Z07" wheels, and their potential fitment on F-bodies. Coming from 'corvetteforum', I am familiar with the wheel and its perfect fitment on C5s (and C6s).
I did a short search, but didn't really find much on actual offset measurements (mm) or multiple vehicle applications. Ace's site was lame, and most other sites just referenced Corvettes or had only diameters and widths (and some kinda high retail pricing).
Some on here have specified 63mm and 53mm as rear offsets, both claiming good fitment with little or no mods/hammerin'. Of course, I understand that tire choice will also affect wheelwell clearance.
I would like to run the 18x9.5"/19x11" combo on a '98 Formula (silver painted wheel on silver hardtop). Probably with 275-35 fronts, 305-30 rears. I would not be against doing some BFH'ing or thin spacers/adjustable panhard, but would really like to avoid using a lugged adapter.

Anyway, my questions are:
Are these only available as 'C5/C6' offsets? Any additional/optional offsets, maybe for the C6Z?
What are the advertised offsets, front and rear?
Do the fronts fit F-bodies without a spacer? Who is using spacers, front OR rear?
Are the Camaro's fenders that much different than the Firebird's?
Are we assuming that the 18x11" and 19x11" are using the same offset?
Anyone have any weights (lbs) for just the wheels?

I see them on ebay for $869 (free shipping), for C5s and C6s. Anyone seen them priced anywhere else (I haven't checked the Corvette vendors, yet)?

Thanks, Joel.

Okay, it looks like Ace makes specific offsets for C6s (not C6Zs), with the 11" rears at a 73mm offset (same as the stock C6 10" wide rears?). I believe the
Ace C6 fronts are spec'd at 53mm offsets.
It looks like the C5 offsets are probably what a guy wants to start with. I have seen the rears called 65mm offsets, and then someone said the C6 rears were another +10mm over the C5 rear Slicks, making that a 63mm offset. So still not 100% sure.
I am also wondering if maybe all their 9.5"s are a 53mm offset.
I saw where someone said, what may or may not have been a general statement, that Ace's 19" rears were 5 pounds heavier than GM C6Z06 rears.

I have them on my car.

18x9.5 / 18x11 with a 275/35 and 295/35

No fitment issues at all, they bolted right up and my car is lowered over 2". No BFH, no spacers, no rolled fenders, no rubbing.

Yeah ZF, I saw your SS and that prompted my search.

Some have said the Firebird fenders 'bulge' a little more than Camaro's. Is there any truth to this? ... an additional 1/4"? 1/2"? more?

It looks like the front Slick 18x9.5" is approx. 22 lbs...?
It looks like the rear Slick 18x11" is approx. 26 lbs...?
Still looking for more on the 19x11".