Wood or steel? Depends on soil. If you can drive a wood stake in, there you go. Length should be enough to hold the footing form in place. I would key the footing, it's a little insurance without much effort. Ideal house design for icf. Lastly, try and find or buy Zonts and Zuckles the're ideal for your situation. Use them as long as you need then box them up and put them on line. Sounds like your build will take some time. A little tip would be to get some mistake paint from the homarama and paint the 2xs that you are going to use. It will keep your 2xs from twisting. Don't forget the ends. They check first with moisture.

Was looking for wood stakes to save on the expense but willing to pony up for steel if it meant getting the highest accuracy for the foundation.

I'll check out the paint.

I've seen a lot of people endorse the Zonts/Zuckles - I've been leaning that way, given my application.

Thank you,
~Kip

I would love to see your progress but I just see a minus symbol where you have linked files.

I see them now.

It looks good. I hope you have a good pour to fill those up.

Very cool....Nice....Thanks for sharing....