I just discovered Barefoot Buttons. I recently purchased a Firehawk and have difficulty hitting the back row of buttons without accidentally pressing the first row beneath it. After a little research, I found these little guys. Incredibly and artfully manufactured. They cost about $10 each (including shipping). A total lifesaver for live performance. (I ordered the Version 1 "Tallboy Acrylic" ones.)
Although I purchased these for my Firehawk, I bet they'd be very useful to the Helix community.
Please note that I am in no way affiliated to the company. Just a very happy customer. I had to share.
Barefootbuttons.com