There are two good reasons you should give your palette a bit of extra height.
Less heat
One. Even if you use low-energy / low-heat bulbs to illuminate your light-box, your palette still gets warm. But stick a small pad on every corner, and now your palette’s not in direct contact with your light-box. This helps keep your paint cool.
Two …
Easier to grind
The little bit of extra height also makes it easier to grind and mix your paint. Reason is, you can keep your blade flatter without scraping your fingers across your light-box. This puts far less strain on your wrist.
And you also do a better job of keeping your glass paint beautiful and fluid.
It all helps …
Especially once summer comes.
More tips and guidance here.