I have a small lump in my index finger and might have to find another way to shoot. What are my options?

The first thing I would do is go see a doctor. You may just have a cyst that could be removed. You would not have to change anything then.

Maybe "two fingers under".  Middle and ring fingers.

Middle and ring finger under with DEEP HOOKS and the index finger lightly on top of the shaft, thumb pad firmly on last digit of little finger. Provides a very clean release and around a 1/3 reduction of finger pinch.

Just one more reason why I shoot both right and left handed...my bow and draw hand are interchangeable...it is generally believed that Fred Bear made the switch to lefty because of an injury to his right hand

DDave