It doesn't really matter what you run beyind 6 weeks out, as long as it is able to maintain your muscle mnass. The last 6 weeks is when steroid selection is important. Since it only takes about 6 weeks or less for the best pre-contest steroids to reach optimal effectiveness (in terms of hardness, density, dryness, etc), you don't need to run stuff like Mast, Anavar, Winstrol, or Halotestin longer than that. You can, but it is not necessary.
There are many different steroids you can use to come into your show in great condition. One of my favorite combos the final 6 weeks is:
Weeks 6-1: Trenbolone acetate (tren is typically started much earlier in the cycle)
Weeks 6-1: Masteron propionate
Weeks 4-1: Superdrol or Dimethazine
Weeks 3-1: Halotestin
Test prop is usually run until about 3 weeks out, at which point I usually drop all test, although not always...it depends on the individual. There is no need to run more than 2 orals...and I have found the best results come from combining a strong oral anabolic and a strong oral androgen, rather than using either 2 androgens or 2 anabolics. As an example, SD is an extremely potent anabolic and Halotestin is an extremely potent androgen. They compliment each other very well. Dimehazine delivers basically the same type of look as SD, but you need to use about 30% more to get the same results. You could also use something like Anavar & Halotestin...or Winstrol & Halotestin, but I prefer SD/Dimethazine, as not only does it keep the user just as dry and hard as Var or Winstrol, but it increases muscle fullness to a MUCH greater degree than either of them. It is the single best drug you can take during the last 4-6 weeks of a diet to maintain muscle fullness.
Trenbolone is usually added at 12 weeks out...and no later than 10. It is such a great fat burner, that it is more beneficial to include it early in the prep instead of waiting until later. Masteron is usually added the last 6 weeks. It is slightly more effective than trenbolone at drying the user out, but tren is at least equally as good of a hardener. Combining both works best.
lastly, make sure to increase your AI dose the last 3 weeks.
As far as steroids are concerned, the combination of AAS above is enough to allow ANYONE to get in their best condition possible...hard & dry like a rock. Of course, other factors play a huge role in whether or not that will happen, but at least you will know you are covered from the drug side of things with that combo. There is no need for any other steroids. Adding more won't improve your physique...it will only cause more stress to the system. As far as dosages go, that is an individual thing, but if I were to choose a mid-range (which is suitable for 95% of all people), it would be right around 500 mg of Trenbolone weekly, 500 mg of Masteron weekly, 30 mg of SD daily, and 30 mg of Halo daily.
I cannot overstate the importance of diet if you want to come in with your best condition. You must lower your BF to around 3%...4% max, but 3% is ideal. If you do that and follow the drug program outlined here...even if you use zero diuretics...you will be hard and dry as nails on contest day even if you don't know how to manipulate your diet to come in dry. If you do know how to manipulate your diet...and you combine it with that other stuff, that is how a BB'r achieves extreme condition....the kind most pros do NOT achieve.