Solomid-copycat for the vertically challenged…

You need about 1 foot all the way around to allow room for the walls to slant up.

I'm 6' 2" and 9 feet works good, so 8 feet should work for you.

Next time I make a tarp I might make it from dutchwaregear.com argon 67 silnylon, but it's currently out of stock

FWIW, I recently weighed the XL Solomid in Silnylon and it came to 17.26 oz, about 7% less than I was expecting. Thanks MLD!

I wonder if the newest batch of SoloMid (regular length) are coming in under spec?

Jerry, where are you seeing Argon silnylon? I though it just had a DWR?

Dutchwaregear used to sell Argon silnylon

Someone made a tent out of it

Now, dutchwaregear doesn't show it

I don't know if they're planning on re-stocking it

Jerry,
I thought Richard N's follow up test on a prior thread showed a lack of waterproofness with the Argon silnylon. Perhaps that is why it is not for sale.

"I thought Richard N's follow up test on a prior thread showed a lack of waterproofness with the Argon silnylon. Perhaps that is why it is not for sale."

Other vendors would sell material anyway : )

Silnylon for floor has to be waterproof

Silnylon for tarp isn't as important. Maybe there's a little misting, but it isn't enough to get your gear wet.

It seems like they could sell it as is.

Somebody made a tarp. I wonder how they thought it held up in rain.

I would recommend 8' length minimum. I tried an 8×8 pyramid tarp once, but I found it just barely too small (I'm 5'6''). I like to account for room to move and slide around at night without having to worry too much about hitting the walls. Your sleeping bag on a sleeping pad can add a lot of bulk while a cat curve can eat up a lot of interior room.

You could look at some of the smaller pyramid tarps for dimension inspiration – shelters like the SMD Lunar Solo/Gatewood Cape or ZPacks Hexamid come to mind as small mids whose dimensions could give you insight. Whatever you decide, try making a prototype out of painters plastic or similar to give you a good idea of the size; it's better to find out your dimensions are too small with the plastic prototype instead of after you've done a bunch of work cutting and sewing!

Regarding Argon silnylon:

"Silnylon for floor has to be waterproof

Silnylon for tarp isn't as important. Maybe there's a little misting, but it isn't enough to get your gear wet."

I agree with Jerry's comments. It's why I chose Argon Sil for my hex pyramid tarp. And 30D silnylon from Lightheart Gear for my floor. I don't think waterproofness is critical with steep shelter walls, but I may prove myself wrong. Summer is the off-season for backpacking in Arizona, so my tarp has not yet seen real rain. I've taken it car camping, but all it got was a little shower (did fine, not even seam-sealed). I'll update my original build thread with its performance once I get to use it more.

That would be interesting to hear your experience with good rain

I've never sealed any seams on a pyramid and never noticed any leakage.

I've always used the cheap silnylon that's not waterproof and occasionally I notice misting, but it's such a small amount of water it doesn't matter. Your skin can detect even a tiny amount of mist.