You will never know unless you get out there and find out!
I continue to be amazed at how little it seems to matter when it comes to NVIS antenna placement. I've been making a habit of purposely setting up with compromised antennas to see if I can still get my message through and so far have not had any issues with 5W and a wire.
I was able to check in on the OEN (Canyonville, OR) from Winchester Bay, OR (102 miles) yesterday with a clear signal and did not notice that my antenna had drooped severely until after net.
Next outing, I plan on just laying it on the ground. If you haven't been experimenting with less than optimal installs, give it a try!
Why? Because you will never know what it takes unless you try.