Hey,

I am planning to make 3 mining rigs. With the following config:

Mobo: Asrock H81 Pro BTC
Gpu: 6xR9 280 (per rig) i.e. 18-R9 280
PSU: Corsair
Ram: Corsair
HDD: WD

Firstly, please tell me if the following config will be good enough or not.
Secondly, how will all these three rigs mine together. As in will using the same configs and details of my pool on all the three rigs will do the thing or is there something else that needs to be done.
Thirdly, I need a minimum monthly income of $1000 and plan to mine DogeCoin, will that be a good choice or not?  If No, then please do suggest me a good AltCoin.

Also, i am expecting the cumulative hashrate to be around 12,000 Khash/s. Am i right?

Thanks