Depends on tire size, but a 1.25" bl and plus or minus 3 inch of suspension is ideal up to a 35" tire.
There is a ton of explaining to do, but I'll try to shortlist some of the basics.
Jeep wheelbase, width, and axles are maxed out at 35 inch tires. Jeep drivelines with are maxed out at about 5 total inches of lift while maintaining the ability to run well balanced travel. In other words, droop without binding.
5 inches is generally gained through a combonation of suspension and tummy tucking. 3" suspension, 2" tucking. Going beyond that, the drivetrain travel becomes limited, and everything becomes a compromise.
A fully built jeep without a tucked tummy is an oxymoron really. Since a smooth belly is essential for good offroad performance.
A proper tuck will provide over 3" of clearence, while only raising the output 2", and moving a minimum amount of the jeeps weight upward which helps maintain a reasonable cog.
A small body lift allows for more shock travel, complete tummy tucking without cutting into the tub, and fuel tank tucking. At the end of the day, 1" of body lift is far more beneficial then 1 more inch of suspension.
3.5" and 2"bl is a good combonation for 37-40" tires but requires high clearence fenders and or cutting to maintian a good travel ratio. That said, it doesnt really matter because once you go to a 37" tire, so many things have to addressed for a jeep properly, and reliably.
Few things that are essential to running more then a 35" tire
1 ton axles or some equivelant (addresses larger balljoints, wheel bearings, axle ujoints, and tie rod ends)
Hydro steering
Increased axle width
Increased wheel base
rim size
bolt pattern
body clearence
etc etc
In short, thats why 35's are discussed, and that why plus or minus 3 inch is considered max for a reliable well balanced wrangler suspension set up.
The absolute max on stock wheelbase is 5.5 total inches of raised about. After that, you start losing suspension travel, and it all becomes a compromise.
hth
And by the way, I have cut apart full traction lifts and repaired them for people for several years now.
They look nice, but honestly, their quality is not there for the money.