Can you not just dig 1x1 holes directly downwards about 20 blocks, in a non unifom pattern and place the panels at the bottom (hide your base there too), you would have to walk directly over them to see them.
People are lazy too so anywhere that would mean building blocks to access would deter them.
Even better, that same Idea but at the bottom of a ravine with no visible resources, they will be too lazy to go down it and all they would see at most is a few 1x1 holes, you could do bigger ones as well as they would not even be able to go directly over them without making a bridge, or jetpacking.