You've clearly thought a lot about this ho!sheep! and I am no expert on hot-composting, but all the things I've read suggest upper temp' of 60-65 degree C, after which beneficial micro-organisms really really start to suffer, apparently. I'm not about to research optimum temp's for dog-poo composting, but seems to me that extremely careful management of composting temp's will be required to sanitize dog-poo and, in the worst case, that your target 70 degree C could potentially halt the effective aerobic break-down of the composting materials. !!??