I've done something similar but simpler.

I took two 20' Bream poles & mounted them on a 1"x 2"x 8' with clamps.
I left a 4' gap between the ends of the poles. Total extended length =
44'.

I then strung #16 wire along the outside of the entire length, feed it
with ladder line thru a tuner & mounted it on a 30' tower.

Walla, a rotatable dipole for 40 meters thru 6 meters (75 meters is a
push but it loads).

It has gain & directivity on 20 - 6.

Total cost - less then $40

Terry
W8EJO