One thing to be clear on, a "normal" overburn means stealing some leadout space on a standard 74 / 80 min CD-R to use for data, at some risk to integrity in that area. It takes an extremely good overburning media to reach even 2 minutes more than capacity.
74 minute media follows the rules.
80 minute media bends the rules, with the tolerances skewed to to the edge of their limits.
90 minute media tears up the rule book, it is by definition, way out of normal tolerance.
99 minute media takes the rule book and makes confetti out of it.
http://www.disc4you.com/index.php?file=cdr99&lang=german - it seems the englisg version is no longer available, bur the drive compatibility table is readable.
If you look at www.cdrinfo.com 's recent reviews, few drives can READ both 90 and 99, and many can't read either.
Only other option is to use a DRIVE that can break the rules, with tricks such as HD-Burn (not well supported) or the other form of density shift - at 20% capacity increase, results may be readable on some other drives, but at 40%, they won't be.