Oil pump Pickup screen

Hi everyone.
I'm getting frustrated and need your help.
I have a k1500. I'm putting a new oil pump in it and having trouble getting the oil screen where it should be. I've been told that it should be 3/8 to 1/2" from the bottom of the pan. I've installed two screens so far and both have been high. This last one will be 1" high if I leave it that way. I've measured the depth of the pan and subtracted 3/8" from that. Installed the pump and measured from the block where the pan bolts on down to the distance I got after subtracting 3/8", marked the tube and pump, installed the screen into the pump to where the marks still line up with the screen tube clear in. Did all that with no gasket on the pan. Put the pump on the block and checked distance from screen to bottom of pan by taping different size bars to the bottom of the screen and put some grease on it so I could tell if they were touching. Went clear to 7/8" before it touched. Plus, when I put the gasket on it will end up being close to 1".
I don't know how deep the oil is in a four quart pan don't know if the screen will be submerged when going up or down hill's so I don't pick up air or not.
Don't know what I'm doing wrong.

What do you guys think?