I was just saying no older then this. He is free to get newer and yes he will have more hash. It all depends on what price he can get gear at. As I think S7 is overkill on .03 cents currently.
If OP can get a deal on S5's or something in that generation yes he will be doing very good at .03 cents. I think with so low electricity a used miner is quicker ROI in most cases (he needs to do ROI math before buying).
You are right he's in a awsome position as far as options. A quick ROI on S5's sounds interesting to me just since quick ROI, then he can add more miners after that. If he got a S7 yes he would be able to use it for quite some time. If we only knew having and what it would do, but it stands a chance of still running on having if BTC value is decent on S7.
So pros/cons on both sides.