If you work for the company I’d tell your bosses if they want thefinalvideo to even look halfway decent you need the source tapes for them or full-res QT files captured from thoe tapes. if you work the way you are now your workflow is going to be highly compressed file -> another compressed format for editing -> anothr highly compressed file. you’re lsoing quality at every stage. If the original is a youtube quality video or something the final piece is going ot look like utter trash.
Reminds me of clients who constantly insist that DVDs are a great format to edit from…..