This hurts really bad on the ROI aspect => for shipping and bringing products in country which is +18% of total cost
I would consider to full all the free electricity you can have access to with some S7. You'll minimize the risk and you are pretty much sure to hit the ROI. Don't forget the resell value of the miners when you'll want to turn them off and/or upgrade them.
As for the one you pay the electricity, it's going to take a long time to hit ROI. We speculate that the new gen of hardware will kill a bunch of old one but i'm pretty sure the Diff will just keep rising, even after the havling. But all of this is speculation. We don't know what will happen.
Bitmain's new chip ?
Bitfury's new chip ?
Whoever's new chip ?
A price war between 2 or 3 of them with the new gen would help us a lot. We know Bitmain and Bitfury have huge pocket but hey also have huge farms to run their new miners. A previous price war between Spondoolies and Bitmain proved to be very profitable but it's also due to a small difficulty increase over a long period of time in 2015.
So there is many unknown elements.
1. When the new gen will be available ?
2. Will it be affordable ?
3. massive difficulty increase or slow increase or even decrease ?
4. The Bitcoin price
Bottom line, just make sure you don't loose your house if everything goes bad. Gamble what you can afford to loose
Hope it helps