tools for resealing a tank.

[Werbo]

IMO you do not need to remove all the silicone from the corner. Remove the silicone that is tattered and has come loose. Then run your masking tape a mm or 2 from the old outside edge of silicone and re-silicone right over.

Use the plastic spoon to give your corner a nice look and then remove the tape.

I'd do the 4 corners let them dry and then do the bottom (if needed).