I used some brass fittings on mine and I have not had any problems.
As for the clear PVC, I used the clear PVC from the Python gravel tube. It is 2" diameter and thickness feels pretty good. I guess if you can get that part cheap in your area, it might be an alternative. Just an idea.
I just finished building one of these. I used the clear plastic tube from an old python. The insides of each end piece that the python went into had to be grinded down a tiny bit to make the plastic fit right. In total the whole thing costed me $12 canadian. I just started it up an hour ago. It built up a pocket within half an hour that I had to burp out manualy by turning the whole thing upside down. But I think this was just the air from my new bottle of yeast and hopefully I won't have to do it again.
Built mine two days ago man what a diff works awesome, I built mine out of ABS can't see in so I just make sure my bubble counter is working I dont really need to sit and what bubbles diffuse lol. Thanks for the article I based mine of this and another. CO2 using two hagen canisters, cause they look pretty lol from 14ppm to 28 varying of course but nice real nice