[300ohm]

I dont know what the problem with the 1/2" pvc tees could be, they are super common and cheap. Ask the store manager.

Dont use coat hanger wire, its too short, paint covered, and less conductive. In Canada, the best option is aluminum rod at Metal Supermarkets. Ask for for the softer stuff, as some is very brittle. 3/16" or 1/4" is fine.

3. NARODs and NAROD reflectors are the same diameters in all the plans, should I try and keep them the same, or does anyone know the difference if one is thicker than the other? I'm wondering if, for instance, the reflectors need to be AT MOST the elements' diameter for optimal results.

The elements and NARODs have been modeled at the same size, so keep them the same size.
The NAROD reflectors can be a bit bigger in diameter. I used 3/8" diameter on one of my models.

 

[300ohm]

Even the guys at HD said they don't make 'em.

They must be from the planet Utapau, heh.

I hope pure might and a few nails on a board can help me do the job.

Yes, thats what I do. One 10 or 12 penny nail in a 2 X 10 banged in half way. And a scrap piece of 2 X 4 to keep the whole thing flat. Basically all you need for tools with aluminum rod is a hammer and a hack saw or large wire clippers. And a file to smooth the ends.