Tarp Help

[hcho]

I am making two Winter Dream tarps. Since I am just working from a drawing I have a couple of questions.

If I edge the tarp with grosgrain, do I still need to hem the 1.1 oz silnylon?

I'm planning on doing the cat cuts by bending a piece of wood to use as a guide. I've read somewhere suggesting 1 inch depth of cut per length of cut. Does this sound right? If so, that would make a 6 inch deep cut on the sides and 3.5 inch deep cuts on the doors.

Thanks

[MrClockWork]

I just started working on my first DIY tarp this weekend. I don't know about the grosgain because I just hemmed the edges of my sil. I am making a hex tarp so on my short sides I did 1"/1' of length but on my long side I went a little deeper, I did a 9" cat cut on a 7'6" side. No rhyme or reason for the depth, just looked about right when I laid out my string.