1. For my first MYOG project, would this be too big of a project to take on?
I agree with others - stuff sack would be good first project. When you try to do a tent, be meticulous laying it out and sewing it. Either use my technique of doing a few hand stitches, or use pins, to line up the long lengths because otherwise the top fabric will drag on the pressure foot so it won't be lined up by the time you get to the bottom.
2. The silnylon used in this article seems pretty heavy. I did find an option that was a little more expensive, but quite a bit lighter: 1.1 oz Ripstop: http://questoutfitters.com/coated.html . Would this be a good option to make this tent lighter?
I used "1.1 oz ripstop". Silnylon. It weighs 1.1 oz per square yard before being coated with silicone. About 1.4 oz per square yard after being coated.
I'de like to try this with Spinaker fabric. It weighs about 1 oz per square yard including the coating. Also, it's polyester so it doesn't stretch as much. Unfortunately, it's not very available. They have problems manufacturing it. Also it's expensive.
Seatle Fabric has polyester spinaker fabric, but it only has a DWR coating and they warn against using it for tents because it is loud in wind. Anyone every use this?
3. If I wanted to make this a larger pyramid...say 9 feet x 9 feet, what dimensions would I use for each section? Or how would I figured this out?
That's funny, my tent just happens to be 9 feet x 9 feet.
That seems large, but because it slopes to the ground, you can't really use the area right next to the edge. The usable area is more like 8 feet x 8 feet.