Yes. That works, too. The best way to create dashed line and of course control line weights is to do it in LayOut.

You are right The standard 'en' template-set does indeed have 'mm' versions - as the 'b' types ['a' types are 'inch']. During ATC training I had to make a 'mm' training-template for the UK, because there isn't one for 'training' - only a=inch/b=meter - so that's where my memory broke down......