Four of a kind is a sweet poker hand, indeed. For pai gow poker purposes, however, it is sometimes better to split it into two pairs. It is NEVER better to split it into three of a kind and a high card hand. To split or not to split, that is the question.
Four of a kind with a pair
In a perfect world your two of a kind would come with a pair. That makes life somewhat easier, but it still not 100% cut and dried. If your extra pair is 55 or lower, you want to split your four of a kind if they are jacks or better. Therefore the hand
Would be better set as
2nd high hand:
High hand:
Four of a kind and three singletons
If your four of a kind comes with three singletons, then use the following guidance to set the hand:
If the four of a kind is 6666 or lower, keep them together
If the four of a kind is 7777 or 8888 keep them together if you have a Q or higher for the 2nd high hand
If the four of a kind is 9999 or TTTT keep them together if you have a K or higher for the 2nd high hand.
If the four of a kind is JJJJ or QQQQ keep them together is you have and ace for the 2nd high hand.
If you have AAA or KKKK, split them
Four of a kind with three of a kind
It's raining cards on you and you have four of a kind and three of a kind. Always put the highest pair possible in the 2nd high hand and put the rest in your high hand.