I have a shelf I want to hang up for my son to put up his gaming console and other expensive items. The studs in my wall don't line up with the shelves mounts. I have some drywall anchors left over from hanging pictures that are rated for 79 lbs in 1/2 inch thick drywall and the mounts require 4 screws, two sets of vertically in line. Can I safely mount the shelf with one side in studs and the other with the drywall anchors if I put the heavier items on the side in the stud? The overall weight of the shelf and all items going on it should weigh less than 79 lbs. The shelf is just over 45 inches long if this is relevant.