Ok, before you continue trying to tackle this project, i'd like to point out that Kamerar will be releasing a new baseplate for the QV-1 LCD View Finder. This new baseplate will allow the QV-1 to fit better with smaller camera systems - which will render this DIY useless for many.
Now because I don't have an exact ETA on when this new baseplate will be released, this project could be useful for the time being. If you already have the Fhugen GH3 cage here's one way to get the inexpensive QV-1 LCD View Finder mounted.
Mounting the baseplate of the QV-1 directly to one of the tripod mounts will not align properly, but it will if you use the actual camera mounting screw to hold both in place.
The Kamerar QV-1 can actually dock directly with a Manfrotto 501PL compatible quick release baseplate or directly to a compatible tripod head (see it in action here). Another benefit is that the QV-1 is offered with a baseplate and set of 15mm rails, so you can now add a follow focus to your setup.
Of course if you're using another system, you can directly attach another QR plate underneath the QV-1 base through one of the threaded mounts. You can find out more about these products at https://PNCGear.com
Fhugen GH3 Cage
Kamerar QV-1 LCD ViewFinder