You should use an open-handed grip as much as possible. Most climbers are weaker open-handed than crimped, so you may find this difficult at first, but you’ll get used to it. Training open-handed will increase your crimp strength (but not vice versa) and it is essential for holding pockets, slopers and certain edges, as well as making moves at maximum stretch and catching dynos. Most importantly using an open hand lowers the potential for injury. As you adapt to training, you can incorporate a little crimp training to increase your maximum edge-holding power, but keep it to a minimum.
Image 1 open-handed:
Image 2 crimped:
(Taken from the Metolius brochure)
