I just use Player's Option: Skills & Power and use the class XP table for the class I draw the most from. So if it is a fighter heavy class, even if it has spell casting, I'll use fighter experience and saves tables.
The 2E DMG had a guide. It wasn't exact though - if you used it to create the 'core' classes, they ended up costing more XP/level. This means that any class built using those guidelines would be at a disadvantage to a 'core' class.
The 2E DMG had a guide. It wasn't exact though - if you used it to create the 'core' classes, they ended up costing more XP/level. This means that any class built using those guidelines would be at a disadvantage to a 'core' class.
The DMG is the best way to get a good feel on creating a new class. You can use its information as a guideline and adjust it how you need to, in my opinion. I've developed classes based on Final Fantasy jobs using this method, but I did later adjust the experience values to more closely fit (albeit slightly higher than, normally) the core classes.