Parametric L-bracket with round countersunk hole

I was searching for a simple yet strong looking l-bracket for a wood cabinet/shelf I'm building. Azdle's parametric L-bracket was the closest I found, but it had odd shaped holes. I changed the design a little to have ordinary countersunk screw holes instead of the original ones.

I've never tried the customizer before myself, but this has some variables for easy adjustment of length, width, thickness, screw size, etc.

Also, check out my corner bracket on https://www.thingiverse.com/thing:2862925

UPDATE: Rewritten from scratch, much simplified and screw holes improved.

UPDATE 2: Rewritten to support different side wall widths, to carry more weight. See example STLs uploaded. Set external_width to 0 to ignore and use the same thickness as the back wall and base.