What is your application? How far does this link have to traverse?
Sure, you can use woks, etc. as reflectors and you will get some gain.
I am reminded of the old "wok fi" web site - a very old web page which is now gone - that had tons of ideas using USB dongles and various reflectors made from cooking utensils, etc. to establish medium range wifi links in new zealand.
https://en.wikipedia.org/wiki/WokFi had a link to it -
https://web.archive.org/web/20140817040813/http://www.usbwifi.orconhosting.net.nz/ )
Note that unless your reflector is mesh its likely to have a lot of wind loading.
A yagi would probably be the easiest high gain 2.4 GHz gain antenna to make.
If you use a dish, use something like a biquad for your feed..
It would likely be the best feed for a repurposed off center feed dish.
Look up Trevor Marshall's design.
http://www.trevormarshall.com/biquad.htmUsing a helical antenna as a feed for a dish is not optimal because of the phase center issue.
Also, just a hunch but the area around the base of your helix doesn't look right. The launching off area is critical for the performance of a helical antenna. You may want a matching stub, some kind of a gamma match.
The N connector should not be in the center, it should be at the base of the helix which is not the same thing.
Also, take care that the piping you use is low RF loss pipe. Some pipe is and some pipe isn't. I went through several different kinds of pipe several years ago building experimental GPS antennas.
Use thin pipe. Very thin plastic pipe.