I'm trying to hack my existing desk to make it a switchable sitting/standing desk. In order to do this my best guess is to add a secondary top and make that top adjustable in height. Is there some kind of lever device that I could implement to move the new top up 10-12 inches (and then subsequently back down)?

The existing desk is a large executive.
66" x 36"
30" height

Trying to achieve about 42" working height.
Approx. 20-25 lbs. of equipment on the surface that needs to travel during actuation.