Making Octavia I HB tailgate pop full open

Just got an Octavia I, it doesn't have remote locking, so that needs to be added.

I really like the tailgate opening feature of the new BMW 500; you get the hatch full open by pressing a button on the remote. I found the necessary solenoid from a nearby hardware store, next some wire and a relay.. So then I get the lock open.

The next question is, how to make the hatch swing full open? I was thinking of a strong compression spring and some stronger pumps to replace the stock ones that hold the gate up once open. Would this work? Or is the hatch just too heavy?

Thanks!