Here are some thoughts:
How do you know the timing chain rail broke? Did you take it apart already or did the shop?
You (or the shop) can determine whether the valves were bent by doing a leak-down test one cylinder at a time. The engine can be rotated by hand (assuming that the chain didn't break) until the valves are closed. Then the cylinder is pumped full of compressed air. The air can only escape past the rings or one of the two valves. Your mechanic will know immediately if there are bent valves.
So, you shouldn't have to spend $1000 to find out the extent of the damage.
Experience is something you don't get until just after you need it.