This forum has been a fantastic resource. I'm within a few days of filling my pool so there's still time for a few mistakes, but here are a few things that might be helpful for others.
1) Get clear and complete information from the city before you start. My first contact indicated I needed structural engineering, so I ordered sealed plans through the pool supplier (TX registered engineer). Permit office said they didn't need them - just a layout but the inspector would need them. The structurals arrived the day the kit was to be delivered. Unfortunately the concrete ring dimensions shown were 12" deep by 42" wide!!! The hole was already dug (through rock) so this was a massive increase on my 24" over-dig. Not to mention a lot of concrete. Apparently some standardized co-efficient of friction tables were updated in 2010 and 24" concrete is not an option - regardless of soil conditions. Kit supplier tried for days to sort it out. In the end I called the city inspector only to find out that Austin TX does not require structurals for pools! Big relief, but I expect others may not be so lucky. I'm comfortable with the 24" wide footing - can't see it going anywhere even with all that water.
2) I was a bit worried about pool kit suppliers. You hear so many bad reports about fly-by-night outfits that provide no support. This was certainly not the case with Sunland pools. They've been very responsive to emails and phone calls. Certainly a good experience for a first time pool builder and owner. I was able to get 48" (vs 42" walls) which I think is a must with older kids.
3) Mini-excavators are easy to use for simple stuff. $300 for the weekend. Digging an accurate hole is not so easy - especially when rock is involved. But do not do what I did and dig yourself into a hole. Stay on ground-level!
4) Tried everything on the rock. Excavator, 14" rock saw, feather/wedges, Dexpan, electric jack hammer. In the end, hard work and the right technique with the jack-hammer took care of the rock.
5) Take care with poly flex-panels. The computer-drilled straps for free-form pools are pretty cool at setting up the shapes, but I was short on the press-washer to hold them in place. Unfortunately some straps popped off and the shape is no longer perfect. Straight/rigid panels seem much stronger.
Hope this helps other DIY'ers.