In the end, I decided to do the lazy trick. To hold Ctrl+Tab and put pixels where the colors are displayed.
I knew it was going to be impossible without this method (that I discovered right before starting to draw...) but it works incredibly well.
That's how it looks like for now, I'm going to bed now. it's 4:22 a.m and I have to get my final results for my BAC at 9:30...yeah I know, I always sleep extremely late when there's important things to do the morning, BUT I LOVE WHAT I'VE DONE.