I followed this advice, and it worked extremely well. The packing tape is the key method for getting the gill off with no fuss, all other methods risk scratching the paint or using too much force, in my opinion.
I did the first gill replacement, and then took videos of the second.
Before you start, it's worth watching all 4 videos (sorry, I don't have time to splice them together) so you know all the steps.
Overall, this is a very simple procedure that even non-mechanically inclined people can do.
Now that I've done one set, I could do 1 gill replace and removal in probably 7-8 minutes, so 15 minutes for both sides.
I hope this is useful.
Part 1 is here:
Part 2 is here
Part 3 is here
Part 4 is here