Your key is 279, combo is 27x,29x,79x, your x is 9,4,1,3,7. Your state at this time has about 90% of distinct draws(123) ,less of 1xx.It will be best to wait for a key.Now your doubles ,from which you pick the key at this time is 944 of 2/25/2012. You can reduce the above combos to 27x,29x/9,4, and 27x,29x/1,3,7 if you have limited bankroll.
Reduced combos: 279,274,299,294 and 271,273,277,291,293,297(valid for 3-4 draws)
Personally, the key put a limit on my spending, I play when I have a key.It will be best to start with the last 10 results, look out for keys from oldest to recent(priority to old keys first),combine keys into combos,your x is mostly from where you got your Keys or the Current draw.
Lets test some examples in your state,between jan 12 to feb 17 of current year,you have 6 doubles;
date drawn key combo results frequency
1/12 994 021 02x,01x,21, 029,052 +1,+2
1/26 636 358 35x,38x,58x 138 ,258 +4,+6
2/10 646 358 35x,38x,58x 635 +3
2/16 552 368 36x,38x,68x yet to draw
2/17 887 130 13x, 10x 30x 137 +8
2/25 944 279 27x,29x,79x yet to draw
Note: Of the 40 drawn results(jan12 to feb 27),you have only 6 keys, you stay focus and make money.Let's interprete this small data above: Your x for this data comes from where you keys were generated,i.e. 9 of 029 came from 994 where key 021 picked,6 of 635 from 646 where key 358 was picked,7 of 137 came from 887 where key 130 was picked(do more backtesting to be comfortable,then you can start to play straight bet!).
Key Combos:The way you combine is very important, a key of 358 for example is not not 853(the position of digits is imposed by this system when the patterns are formed),do a back testing of many keys in the 123 format, you'll be surprised to find that 12,13 is more frequent than 23, with this info your picks will be reduced ,and you can play around with 12,13(21,31).
Frequency:Number of draws after a key is picked(do backtesting to find your range,it takes about 10 minutes to work on 60 draws,just take a glance with the table and write the frequencies down).
Remember your keys could be many the next month, choosing of x is not rigid, I am giving a guide,you have study the trend and keep to it, without jumping all over 'cos you dealing with random event!Good luck