1600k/hashes I'd say is plenty but, if you're going to solo mine any low difficulty coin you need to think long term otherwise you'll just end up with the same sort of money as if you were doing pool mining on a high difficulty coin, you'll only ever really make money off mining at all these days if you do long term trading with the coins you've gathered.

The people who made the serious cash with Bitcoin and Litecoin I reckon are the ones who built up their stash when the difficulty was extremely low and then waited for a year or so for a price rise to happen.