Best practice to "pre-shear" ink before introduction to the screen. Do this slicing and folding the with an ink spatula. Do NOT mix with a power drill, friction from mechanical mixers other than a "turn about" style mixer will thicken up the ink body.
If ink climbs the squeegee, the ink has not been mechanically sheered enough. Carefully transfer ink into a container and shear with a paint knife, cutting and folding over on itself as you stir the ink.
Maximum Opacity is achieved thru 86 to 155 mesh on a manual press and up to 230 mesh on an automatic press.
Screens should be at least 18 newtons, although mid 20 is ideal. Low tension decreases opacity, increases texturing and loss of edge defintion.
Screens should be coated 1/2 or 2/2 coats to achieve 15 to 20% EOM, to thin of a stencil makes opacity difficult.