I believe every position your picking hand is in lends itself to a technique. I do a lot of studying of techniques with the picking hand and try to focus on the most natural and less physical movements of that hand.

Most of your muting will be with your right hand (palm blocking) and if it is resting on the metal pickup guard that is raised above the strings, you won't be able to palm block.  So you will then be limiting yourself to just one technique for muting, and that would be pick muting (blocking).

Also, to move your hand from that position on the pickup guard to the strings is quite a movement and not a timely physical movement and would create a too much difference in hand position. So I believe it takes away from a natural hand postion and would be too much movement for the hand to move in and out of postions.

Now, as with anything, if you practice it alot, you can overcome many obstacles and it could turn out to be a fluid movement and almost effortless eventually, but I would most certainly try and develop something consistent in hand postition and the basic two picking techniques before I add any other techniques for a certain style or variation in picking.