Higher humidity needed!

[Matorchid]

Hello all,
Hope everyone's day goes well!
I need to get higher humidity, and I do you were of the trick of putting rocks in the tray and setting orchid pot on top of the rocks,oh, with the bottom of the pot not touching the water. With this being practiced so much, can a tray within a tray work just as well. Ie. 4in pot in 8in tray with 6in tray flipped over and maybe some holes in 6in tray to keep it from lifting or floating.
Asking because I need to increase the humidity around my orchids, and I have some gravel for a few, but not enough for all. I have not read this any where, but is the some reason this couldn't be done?

Thank you all for your input, Have a glorious day.