Push Block v4 (threaded inserts ed., no supports!)

I've worked on two editions of remix of the excellent push block design by Trobinou (January 23, 2017). One of my remixes does not make use of threaded inserts, while the other (this one) does. (I have not yet posted the non-threaded-insert version of my remix yet. If I get it posted, I'll revise this and link to it here.)BOM and AssemblyThe following “bill of materials” is from the original listing that I remixed to improve: BOM:Optional: tap (Ø4 mm) to fix the sides — (note: I did not use a tap on mine, if I remember correctly)Two (2) screws, M5×30/35 mm, for the handleTwo (2) nuts, M5, for the handleEight (8) screws, M4×16 mm, for the sides — (note: the original listing spec'd a stainless steel screw with a flange, aka “TBHC BASE PLATE A2”) but I did not buy or use any such special hardware. I just used a regular M4×16 mm screw without any special flange.)Six (6) hexagonal head bolts/screws, M4×20mm, for the knobs (original listing spec'd this one)Six (6) nuts, M4, f