All tie specs are found online so I would just call the company and ask what type of tie they would use in this situation. They don't need to know your name or project specifics!
The tie spacing depends on the amount of concrete in the form, which subjects a pour pressure on the plywood/timber...
We use ties from Dayton Superior because it's what the local contractors use. They can tell you the tie breaking strength and you can figure the number of ties you need from there.
sniper98, I could not find a link online at all. Buy it now and claim it on your taxes as a business expense for 2011. I personally think it's ridiculous it's not included in the NBCC code, its essential!
As someone who uses the commentaries often, I suggest you bite the bullet and buy them. I am not sure how you would do any sort of wind or snow drift analysis without them. The new 2010 commentaries are now out and are well worth the cost.