UPDATE:

Added a version with a base plate thickness of 1.5mm as opposed to the 2mm of the original.

Quad FPV Stack Adapter Plate

Originally designed for the Caddx Turtle V2 with HD DVR on the board as the supplied solution was, in my opinion, crap and not fit for purpose.

Quad FPV stack adapter plate to fit a 20mm x 20mm board to a 30.5mm x 30.5mm stack.

The small diameter stand-offs are needed to miss components crammed onto the Caddx board but even then they may still need a little sanding to get clearance. You will need to use M2 x 5 or 6mm long self tapping screws with a head diameter of no more than 3.5mm to clear the components on the Caddx board. The 20x20 holes don't go right through as I've left 0.2mm for the first layer for printing purposes.