That's ambitous! About 12 years ago I poured a 16x24 foot slab in three sections as you are doing; I bought a dump truck load of sand and a lot of Portland cement. I approached reinforcing a bit differently. Rather than chairs I poured 2"x12" strips, 5 feet OC for the full length. I then used mesh which somebody had given me, with enough rebar to keep it from sagging. That allowed me to drive my 5' mixer and tractor up the strips to where I needed them without ruining the reinforcement.
It's a lot of work, I don't know if I could do it now.