Neil,
I am pretty certain we are on different wavelengths here. I thought your draughtsman was re-drawing these submissions, not editing them. Most of the stuff that appears in the mag would take very little time to model and draw by a professional using industry standard CAD. I design for a living and use Solidworks for all my work – non of your problems apply using this. Lines/dimensions/leaders etc all have a "fixed" style set in system options that you can change at will. Once set, the geometry is separate from these settings and is treated as theoretical lines with zero thickness. We don't use poly lines! (aren't they a throwback to the days when cad was for architects?).
If you are not doing it like this (redrawing the projects) then why don't you find a youngster learning draughting and pay them to do a "proper job"? That way the thing would get checked properly for errors and the system makes perfect drawings for you in no time at all.
As with a few others on here, I would always re-draw anything I see to ensure I only cut once!
Mark