Tablet Holders: https://www.amazon.com/gp/product/B07N1DNDYK/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Clamps: https://www.amazon.com/gp/product/B07L9TNSCD/ref=ppx_yo_dt_b_asin_title_o01_s01?ie=UTF8&psc=1

They are reasonably stable, the less thick the board is, the better. My Iris or Quefrency is flatter without the stacked case like a HHKB would fit better. If I end up sticking with this I'd use some industrial strength velcro to secure it.