The default method to hold the VAT down in the Lite3DP is with two magnets. I found it to not be super reliable so I designed these two brackets that you can easily screw on the existing screw holes and slide the tray in and out.
It has two notches that fits with the middle screw of the custom VAT I designed (also available here: https://www.printables.com/model/153275-lite3dp-tray-vat-8-screws) but it should work perfectly fine with the stock VAT or any other without the middle screws.
The author hasn't provided the model origin yet.