A tophat is preferable above a coil, certainly in the bottom of the antenna.
If you are trying to keep it low, a hi - Q coil and tophat at the top, and 6 to 7 meters for 80 meters.( 20 feet or so)
I made the same for 160 and got reasonable results, the main important thing to remember with verticals is the ground, with a vertical dipole or corner dipole, inverted V or al L fed at the top might give good results as well.

But a pure ( shortened ) vertical really needs lots of ground wires...
ON4UN Low band DXing gave me lots of good tips, it's here on the H.D. as antenna book.
I used army glassfiber poles 4 feet long camo green that can be connected to make a longer pole, mine went up to 9 meters just with a few tie down lines at 1/2 way up.strong enough to carry a tophat and small coil at the top.
Not advisable for force 8 gale and above ;)