Great job, and welcome to the forum!
Just a bit of advice: stickers really make or break a puzzle. Try to cut them just a bit smaller next time, and it will make it look just a little bit nicer overall.
But nice mod! I'm impressed with the quality, love the fluorescent stickers, are they postit notes?
What did you fill the pieces with?
PS http://www.sarastoystore.com/products/G ... Parts.html
just tell them what part you need and they will sell it to you. Good luck!
I capped the pieces with some plastic from a storebought 3x3 package
I used some vinyl sheet from cubesmith for the stickers.
I asked if they sold cores there and they dont sadly