I have spent some time designing diverse shapes for hotbed clamps. My favourite one is the "Hotbed Clamp Straight".
I recommend printing the clamp vertically. This is to get the layers of the clamp perpendicular to the side of the bed and so to minimise the risk of layer delimitation, specially with thin wall width.
Hotbed Straight Clamp V1_1: see the corresponding 2D drawing
Hotbed Angled Clamp V1_1: see the "Hotbed Angled Screw Clamp V1_1" 2D drawing
Hotbed Angled Screw Clamp V1_1; see the corresponding 2D drawing
The design of the clamps -all versions, is completely parametric so it is very easy for me to adapt the size to specific needs. Just drop me a message if you would you like me to publish a STL file with your specific dimensions. You can find the parameters/dimensions I need on the pdf documents showing the 2D drawing.