Topband: OB804020 shunt feed tower

[FLAVIO]

Hi Topbanders,

I'm about installing an Optibeam OB804020 on a tower of  21m x 0,70m + 1m 
mast ( tot 22m ) .
There are 3 monoband  antennas on the same  16,60 m. boom       : 5 el on 
20m, 3 el. on 40m.,  2 el. on 80m.
All the elements are elecrically INSULATED from the boom and the boom is not 
insulated from the mast.
I'd like to shunt feed the tower to work on 160 m , using the top antenna as 
a  hat capacitor .
I'd like to know how the insulated elements interact with the shunt fed 
tower, either in positive or negative way. Just the boom is electrically 
connected.

Do you think it will work  on 160m ?

Thanks in advanced for any reply.
Best 73's
Flavio IK1YDB