Yup, ur right on track… clean it out as best u can with the dremel, #40 then sand/buff back to clear. #16 will do absolutely nothing here for u other than make those puddles full of bubbles lol…
#16 is basically “craft glue”… it has its use for temporary or very mild repairs not under pressure.
If u dont get those gouges full first go u can sand and do as many layers of 40 as you need. It adheres to itself very well. A pint of #40 will be plenty for the job


. Tank seams look great and seems to be built well, nice pickup for sure as those spots should b easy to fill.