Yeah, you don't need welding gloves. That would be a bit ridiculous. I hardly ever use gloves anymore. Even when I do, it's usually only when removing scrims or lenses while a lamp is burning.
As for your foam core/bead board, 3/16", 1/2", and 1" are the typical sizes. It doesn't really matter what height/width you get. You can even cut it up to fit your needs.
I don't know if I would trust that cheap of dimmer. If you're trying to stay cheap, just build your own in-line out of a socket dimmer and socket adapters on each end. It will be good for dimming down your china balls or blown out practicals in your interview setups.
As for stands, agreed with Scott, rent. You can also rent a 4x frame when needed.
As for a DIY PVC frame, I actually built one (8x) several years ago just for shits and giggles. It ended up being sort of pricey for what I was expecting to pay (~$40), but I did come up with the most sturdy possible build, which was still wobbly. That being said, I wouldn't do it again. Just rent whatever you need. Should you ever be on a tight budget without the ability to rent a larger frame like a 12x or 20x, then you may build one and rig it in its position to stay firm -- not ideal but acceptable on a micro-budget.
Edit: Ha! First post! Have been a lurker for a couple years, finally joined last year, and now finally made a post.
Edited by Kyran Ford, 28 August 2013 - 05:40 PM.