K-factor solidworks

Hi all, does anyone have any sort of standard k-factor used for Aluminum 1,6mm up to 6mm?

I have been having real issues with what I have drawn(cut sizes and the final folded plate). either too big or too small

I have been using (0,27 for 1,6mm) and (0,334 for 3mm) and (0,5 for 4mm.) would a gauge table be a better option?