I work on solidworks 2016 and I regularly convert my drawings to DWG to send them to my subcontractors.
The weight of the Solidworks drawing file is very correct (between 80 and 100 KB) on the other hand when I do the conversion to DWG the plan is at 17 MB.
I have to open the DWG file on draftsight to remove the company logo image and find a correct file size.