Although grip shape can make your experience a little more (or less) comfortable, from a shootability standpoint there is very little difference between a straight, mild dished, and mild locator Hill grip. Aesthetically I don't care for the looks of locators on Hill bows (a personal thing), but the real key with any of these grip types is to learn how to hold the bow properly in your hand. For most people what works best with these bows is quite a bit different than what works best for recurves.
You might do a search on past Hill threads here, there are some good pics posted that can help. You'll still need to experiment on your own, but the pics are a good starting point. I find that full hand contact with the grip (hold it like a firm handshake, not like a dainty teacup) makes these bows feel and shoot much better. Try some different hand holds and see what feels/works best for you. You might also ask the bowyer Craig Ekin what he recommends. Other than yourself (via some experimentation) nobody else would have better advice on Hill "how-to" than Craig.