Add height and width to Google Docs embed code: height="400" width="100%" frameborder="0"
between iframe and src=
Estimate the height (in pixels). Google Slides embed code already contains this info.
Add Date and Initials to Column D: If there is a past date already in the cell, right click in the CELL. Select Insert CELL --> Insert Cells & Shift Right. Add your date and initials to the empty cell. This keeps a record of dates of completion without having to scroll.