I look for a tutorial that explains how to mining vanilla and how optimized the AMD Radeon r9 280x for 400 Mh / s
Just download Smolen's miner and run it. I wouldn't advise to buy a GPU just now for mining Vanillacoins (or anything else) though, since block rewards dropped to 88 and FPGA's are just around the corner which will be far better in terms of energy efficiency.
But if you plan on buying a good GPU anyway for gaming and etc., go on.
I don't agree, you can find good used R9 280x for funny prices and FPGA miners wont kill GPU mining in terms of hash. The real advantage of FPGA's is in low power consumption which means almost nothing if someone wants to mine with 1 or 2 cards from gamer PC when PC isn't in the gaming purpose use and specialy if someone else is paying electricity bills
Buying a GPU just for mining right now, to mine VNL, means you'll never see that money back at current valuation and difficulty.
I wasn't suggesting buying 10 cards, but you obviously didn't read what I wrote, but yes if the guy is in buying only for mining and only for VNL then it's better to wait and buy FPGA once the miner is ready.