I refuse to use straps, I just make my hands stronger. My grip is wayyy behind because of years of straps. Now I use Kroc rows(high rep DB rows), some gripper work, farmers walks, and a few other things I really feel its better to make your week points stronger as opposed to "help" them and keep them week just my .002
BTW I use a double overhand grip as long as I can and then switch to over under