Yeah, I would use what you found them on. I only see C. punctulata on a very specific type of hard- packed, clay/sand soil, but wherever I see that soil there's always C. punctulata.
Bear in mind that tiger beetles won't behave naturally unless you use a hot light bulb to simulate the sun, but that will make the substrate dry out quickly. A water bowl with damp sand is a good idea. If you keep them warm and well- lit, though, they're real fun to watch and feed.
I've had tiger beetles mate and oviposit, but the resulting larvae only lasted a few weeks because I couldn't get them enough small live food. Perhaps you'll have better luck than me if you have a culture of flightless fruitflies, bean weevils, dwarf isopods or anything like that.
Just wondering, why are tiger beetles an indicator of a pristine habitat? I see C. repanda anywhere sand meets freshwater, and C. punctulata has supposedly developed pesticide resistance from its occurrence in agricultural fields.