Switching regulator: How to determine maximum inductor current?
Linear has excellent datasheets with lots of application information, calculations and component selection. This datasheet is no exception. On page 16:  


  The inductor current ripple ΔIL is typically set to 20% to 40% of the maximum inductor current at boost mode VIN(MIN).


Yes, they're long datasheets, but worth reading from beginning to end.