imho, there is no "proper grip" to any bow, only the grip that is most consistent for you, the shooter, and no one else.
imho, in the best of all worlds, there should be one pressure point of contact 'tween the back of the bow handle, as close to the arrow shelf as possible to reduce any unwanted leverage, and some single point of the bowhand's palm.
no, not the entire palm of the hand, just one point. if you reference asbell's latest gem, 'advanced instinctive shooting for bowhunters', you'll see the best general area for the bowhand pressure point nicely depicted.
once you have found that sweet pressure point spot (which should be almost too easy to feel), the rest of the hand - the palm and fingers - exert ZERO PRESSURE on the handle. this allows the bow to pivot on your bow hand's pressure point and will prevent the common 'heeling' of the bowhand on release that cause so many bad arrows.
the bowhand's forefinger and thumb touch, thus holding the bow from punching out of yer bowhand upon release.
this type of bowhand pressure point also allows the bottom of the bowhand (pinky et al) to angle slightly away from the riser/arrow shelf, which gives lots of bowstring clearance on release. it also demands that you need to do what you should be doing all the time - using yer back muscles to 'push-pull' as you aim and release.
you can use this type of single pressure point grip with most any type of handle grip - straight, dished, soft locator or recurve pistol.
it is easier to find that pressure spot with a soft locator grip. you can wrap a straight grip with one turn of 1/8" leather right under where your pressure is located for quicker reference.