Bluto,
Don't get me wrong...experimental aviation has an increadible amount to offer, and merely because it isn't production industry standard, doesn't mean it's a bad idea...experimental aviation has laid the backbone for much of our current light single engine airplane production fleet today, and has been at the heart of everything from the Wright Brothers efforts and successes to Mr. Melville's excursion in the first private vehicle in space (or nearly so).
I have to draw the line in common sense at doing fabric covering with Walmart paint, however. There are limits. There's no reason you couldn't complete the design, if it's a proven one, and cover it with Stits or ceconite. No reason at all. It's simple, relatively inexpensive, easy to do, and you will easily be able to find help in the experimental community around you (sadly, few mechanics have much of a hand in fabric work any more).
If I understood you correctly at the outset of this thread, you have purchased many of the materials. That the designer intends to use aircraft grade hardware is a good thing...I'd go so far as to use aircraft grade rivets, too...unlike the previously mentioned teenie two, which appears to have used mostly ace hardware blind rivets. Then again, lots of ultralight framing is done that very way.
I'm making extremely slow progress (read, stopped altogether, for now) on a Sorrell Guppy, presently...also plans built with hand drawn plans at that...I mean, free hand drawn plans. On 8X11 sheets of paper, no less. Xeroxed...you get the idea. There's no reason you can't build a workable aircraft...just be careful, don't take anything for granted, try to speak to as many builders of the same type design as you can, and in the process, get as much consultation from knowledgable mechanics, builders, and counselors (EAA has an excellent counselor network) as you are able.
Remember that designers of experimental aircraft and other builders often have little experience themselves...don't assume anything has been tested or engineered beyond what an eyeball and pencil and eraser could do...but don't re-engineer without getting some good experienced insight into what you're doing.
The case of the fabric would be a definite place to start stepping outside the plans. I don't care how proven they think it is, coating a fabric surface with walmart houseplaint and sealing it with anything called "son of a gun" can't be good...and there are time proven methods readily available to you that are safe, easy, inexpensive, and durable. Go with those, under the tutelage and support of someone who has done it before.
Don't get discouraged this early in the game. You've got plenty of long evenings to go that will give you plenty of time to get discouraged in the future. If you can just get the fuselage on the gear and sit in it, you can close the garage door, make airplane noises, and will yourself through the remainder of the project. Good luck!!
