as far as the slope is concerned. extra data are available
I've never seen or flown a jet aircraft* approved for more than 3.5 degree slope nor any supplmental charts for more than 3.5. But I have been retired for over six years, so perhaps that has changed?
By the way, the 3.0/3.5 slope is a certification limit set by the FAA, not the manufacture. I do know that certain 121 aircraft and the assoicated 121 operator can have modified performance data, but this is rare and is only granted on a case to case basis after numerous test flights and performance tests.
Balancing the field is just one of the options, not all of them.
Having a balanced field in jet aircraft under FAR Part 91 is not an option.
As for a legal takoff/departure profile, either you make it or you don't. You don't and takoff anyway, it is illegal under US FARs. Not to mention the insurance underwriters and what they would say if you had an accident or incident.
* Jet aircraft flown/operated; Jet Commander 1121/1121B/1123 Commodore Jet, Lear 24/25/28/35, Westwind I/II, CE-500, Lockheed JetStar -8/-731, Sabre 40/60/65/80, Falcon 50/50EX/900EX and Boeing 727-100/200.