The best tying I have found for Ground blinds is, to build one as good as you think you need it, get in it and take a pic of yourself.
This will let you see what "they" are seeing.
sometimes you need more stuff and sometimes less. I like to brush them up as much as possible and leave smalll (8inch or so) holes to shoot through. typicaly they are 4 feet tall. They dont have to conceal you completely, In fact you can get away with tnothing in front if you have a lot of backcover. Back cover is most important.
Heres one that brought deer and bobcats into my lap
and no blind with a ghillie