You should be fine with the dual 1000w PSU option. I have a 7 card gtx 1070 rig with dual 750w PSU's running fine. I also have a 7 card 1060 rig on a single 1000w psu. It looks like you made a mistake with the quantity for the Risers. You have a quantity of 16 for a 6 pack, which will be a total of 96 risers. Also you should be looking at cutting costs. Remember every bit you spend on the rigs is more days that you have to mine before you actually start making a profit. I would use a cheaper motherboard, cpu and ram.
And lastly, think real hard before jumping in to mining, especially now and dropping that type of cash. Two 8 card gtx 1070 rigs is going to produce a lot of heat and use up a good amount of electricity running 24/7. And you will have a lot of down time initially when trying to set things up.