You seem enamored with the HD Stacker. If it has at least 18dB of forward gain without any amplifier, then, in theory, it could have a chance at receiving WAGV.
Because I can't locate any information other than anecdotal reports and testimonials, I don't know what the real gain of the HD Stacker is. Judging from the photos I've seen, I would guess that it may offer between 8 and 12 dB of gain in the UHF band. I won't recommend the HD Stacker to you or anyone else, because there are many other antennas available that have published specifications which are recognized as trustworthy.
If you truly want an antenna with the gain required in your situation, look at the commercial products by Wade / Taco. Here is a bit of information on
site built high gain antennas. Here is an experimental project that might have merit if all conditions needed were available.
Hilltop Antenna Linked via Wifi