It depends.
If you are an equipped lifter, you tend to have a wider grip to take advantage of the shirt.
If you are a raw lifter, generally lighter body weight guys can get away with a wide grip. Bigger guys need a slightly narrower grip. Also, in the IPF, at least one finger must be touching the ring on the bar, so super wide grip is not an option.
Bottom line is that you need to find out what works for you today, cos tomorrow it may be different.
For myself, I can't do a wide trip as it destroys my shoulders. When I carried a shoulder injury for about a year I had a narrow grip but now that its fixed I am back out to my normal position, with ring finger on the rings.