1. I like to lay a trash bag down on my table when sculpting, and tape it down securely. This leaves enough give in the plastic that when I peel off a super thin slab of apoxie, that it can pull off easier. Flat on a table is harder to manage.. There is no yield.. Alternatively, you can roll it out between two sheets of wax paper, then just peel the paper off. Or so I hear.
2. I honesty eyeball it. You certainly could make yourself a pattern, but for me, it is trial and error. I roll a piece out, then I cut out the general shape that I need, a bit bigger than I think I need. I fit it t the pony and trim it down if it is too big, or if it winds up too small, I mash it up and roll it all out again, or add on to it after it has dried.
If doing a dress or something with lots of drapes and folds, just do a small bit at a time. If you finish a section that looks great and folds nice, stop there and let it dry before doing more, or you will just collapse the folds.
3. Couldn't say, as I haven't done any.
4. Pop suggested a pair to me that work great. Let me see if I can find the links.
http://www.bearair.com/Paasche-VL1-Airbrush-055mm/productinfo/100081/ If you do get a brush from here, they do not come with hoses.
http://www.tcpglobal.com/airbrushdepot/compress.aspx#abd_tc20 This compressor also did not come with a hose.
I had to buy the hose separate. And then it didn't fit on the bulky dealybob attached to the side. That thing has a smaller hole than the compressor, so I need to find a converter. The hose DOES hook straight into the compressor and works great though.
I'm really happy with it. I also bought a table clamp airbrush holder, because if you use the cup instead of a jar, and need to set it down, it's extremely hard to do so without spilling. I also got some cheap smallish squeeze bottles at Hobby Lobby to mix my paint in, so I can then just squirt it into the cup. They are really convenient.