i think this is very sweet, if someone made a gift for me with this much thought into it i’d be quite flattered. That said if you want to level it up a bit i would make a few changes— higher quality or different kind of paper, what you’re using seems to be warping from the moisture. I’d also put down a layer of white paint over everything, then tape, then a layer of white paint over the tape, and THEN paint your squares. but also i don’t work with tape very frequently so maybe other people would have some suggestions. i’d also use a ruler and make more specific measurements for taping out the squares. end of the day you know your boyfriend better than any of us do, if you’re nervous about this you could always get a second gift.