I scaled too 500% for my extension cord.

Print one first to check scaling, then as many as you need. In Cura you can left click and multiply selected model.

To attach, clip the piece on the cable, then loosen your baseboard a little (I just pried it loose a bit with a flat head screw driver.) stuff the flat part between the board and the wall.

Anet

A8

No

3mm brim should be fine.