bdosborn wrote:The only problem is that 3/4" plywood isn't really 3/4". It's a little thinner and it makes it hard to insulate as 3/4" insulation is 3/4".
That will be your only problem with using ply. In order to get true 3/4" thickness ply will have to buy hardwood veneer ply, which will end up costing you a lot of $$$. Non hardwood veneer plywood at 3/4" is actually 23/32". Structurally ply is fine for framing though.
I assume you're looking at firring strips from a big box store for the 1x2's? These are grade 3 lumber which you will most likely never find a straight, usable piece. Go with "select", it will be straight and have the dimensional size you need for the insulation.
I went with 1x2's and 2x2's and bought them from a lumber yard, not a big box store. Lumber yard's will almost always have a better quality product and you'll have more lumber to choose from to find the best pieces. Also for small stock like this I used an inside lumberyard, where the lumber is stored in a temperature and humidity controlled environment.
You'll pay a little bit more for select, but in my opinion, it's well worth it. It's important your framing be plumb, square and level, as any variances will only increase how much off square things are later in the build. It's a domino effect.