I expected to be disappointed when I looked at your first piano key border (after your initial post), but no, when I looked, I liked it a lot. I'd leave it, and bind in black and consider it beautiful!
But I also am confused as to why it took 2 days to do the first side? Are you doing a certain repeat or pattern? I'd just sit and sew strips together, take them to the rotary mat and cut them to size, and combine them. Seems like it would go fast enough that way. I've done piano key borders and that is how I've done them. They are tedious compared to just plain borders, but the effect is great.
But it would look fine without the piano key border, too. I just think it is perfect!!!