It's important to find out what type of grip the bow was made for.If you use a different type of grip, you will be applying torgue. As long as you feel comfortable about the consistancy of the torque, then I guess it's OK. But I'd suggest using the grip the bow was made for. There will only be one center of pressure on the bow handle. Personally, I like a high grip on my recurves. Try holding your bow forearm parallel to the ground now totally relax your wrist. Your hand will sort of hang. Turn the wrist out just a bit. Now take the "V" from your draw hand and place it inside the "V" in your bow hand and push back hard. There should not be any give in your wrist at all. That is basically how I like hold the recurve. Now I place only my index finger around the back and kind of touch my thumb around the back. My other three fingers really do not touch the riser at all. As you can tell it is loose, but will not fall out of my hand.
Here is an excert from an article which describes the center of pressure a bit.
When you are pushing the bow grip with your bow hand you are applying a varying amount of pressure over an area. This pressure over an area can be represented (it has physically the same effect) as a pressure being applied at a single point - the centre of pressure (COP). What happens is that from shot to shot the position of the COP moves about and it is this variation in COP position that affects how the bow behaves and where the arrow goes. The torque itself is generated not by the action of the bow hand but by the mechanical action of the bow.
The bowhand COP has two effects, static and dynamic. For example suppose the COP is lower then the ideal position, what is often called 'heeling' the bow. (My heels are at the end of my legs not the ends of my arms - but there you go). When you draw the bow the lower COP results in the lower limb being drawn more than the upper limb so you end up at full draw with a limb with a different 'static' configuration which affects what happens on the loose. Again suppose the COP is horizontally dispaced from the ideal position. When the arrow is drawn the bow is twisted, the riser rotating horizontally in one direction and the limbs being twisted in the opposite direction. At full draw you again end up with a different 'static' configuration. When the arrow is released the various bits of the bow/arrow are accelerated 'naturally' generating a variety of torques. How these torques overall effect the bow dynamically is influenced by the position of the COP. The overall behaviour of the bow, and hence the arrow, is affected by the combination of 'static' and 'natural' torques both of which are influenced by the position of the COP