I haven't seen issues with the advance timing light with the 6al's and 7al2's, if you're running a low side chip in the 2 step you may have to remove it, if it's close to the 3,000 rpm range.I do think there could be issues with the new digital boxes. I have never used the newer boxes so i have no experience in that area.
David brings up a good point with the battery powered timing light, you wouldn't have feed back to the electrical system with those. Most of the racing balancers are marked 360 degrees so a conventional light works fine in most cases.
Doen't MSD, sell an advance timing light, don't know just asking?
JMO
Zip.