I'm using the full dual layered ISO that i riped of my disc and im at about 7417 mb (yeah a lot but its dual layered) but anyway is there really a limit to how big it can be?
Depends on what yr using to load the codes. Gecko os let's u use like a [censored] ton of lines but other ones usually don't. I know the usb loader gx let's u use more than 256 lines kuz I have a lot of codes on and it still works for me.