Worst workaholic I've known was an LSE with heavy elements of enneagram 1, 3, 6, and 8. He was also one of the worst leaders I've had the displeasure of being under. But in general, most often it's LSE/ESE and SEE/SLE that end up being workaholics. I don't really understand it, but it seems they all have in common a sense of meaning or fulfillment in working, much moreso than other types.