Experiences with making bootable slack install cds
 

I've been making and burning my own slack isos for some time now, but since slack 9.0 and the advent of cdrtools 2 I have had the occasional problem getting the cd to boot on some PCs, even brand new ones. I make my isos with a script that uses the same parameters as in isolinux/README.TXT on the slack install cd.
Have any of you encountered a similar problem, and/or do any of you have a suggestion? I suspect that it has to do with the boot-load-size, but I haven't played with that yet.