I'd be happy with that kind of return, the problem is that it all depends on delivery on time, if that slips 2 weeks you will be making a loss, and given every asic manufacturers inability to deliver on time thus far not worth the risk.

Predicting 3-4 months into the future is idiotic during this current rate of network growth, so I've reached my limit of pre-orders. I'd be prepared to gamble on a smaller device with a better risk/return ratio but not 8k or 16k