Well running 256 on BTC is best bet at the moment really. The S3's setup different and pointing at a different coin could be more lucrative then renting them out. As far as the GPUs, mining smartcash, LTC, nicehash, or really any of the older coins isn't very profitable in terms of cost. As far as investing. You could do what I always have done. I have found tokens and others I have been watching. Timing is a big part of everything. Like getting in on 10% daily compounding tokens ect. As far as the investment would go, I would take 20% of profits and invest the other 80%. If you want to talk more about it. You are more than welcome to get in touch with me if you want. Perhaps I can point you in a direction that might be more profitable.