I did a cycle of Superdrol last summer and most of my gains came by the end of the second week. I'm not saying I didn't gain anything during the third week, but in my opinion the increased side effects experienced during the third week weren't worth the size and strength I gained. I maybe gained another pound or two at the most during my third week, and while I continued to gain strength, it just wasn't worth it in retrospect.
So my suggestion would be to run Superdrol for two weeks, dosing 10mg ED for the first three days to make sure you have any sudden adverse reactions, then bump the dose to 20mg ED for the duration of the cycle. I suggest a PCT with tamoxifen for 3 weeks at 40/30/20, or 40/20/20. I assume you already know how to use support supplements and what your diet and training should look like.
So your cycle and PCT would last five weeks, then you could take a week or two off, then run another two week cycle and three week PCT just like before.
In the end you'd definitely gain more from two close back-to-back two week cycles than you would with just one three week cycle, and you'd probably experience less side effects in the long run.
Or you could do a three week cycle, dosing 10mg ED for the first few days followed by 20mg ED for the duration of the cycle, followed by a 4 week PCT dosing tamoxifen at 40/40/20/20. Of course the longer you run any compound like this the more side effects you're going to experience.
I personally like the idea of two shorter cycles due to the fact that the harshness of side effects will likely be diminished (as compared to a longer cycle), you'll gain more size and strength in the end, and since it's shorter it's easier to not start slacking off towards the end as some people do with longer cycles. You could also check out the pulsing technique.
One thing I'll stress though is not to increase your dose past 20mg ED. 20mg ED will be just fine for you, and dosing something like 30mg ED would only increase negative side effects. During the second week is when you'll start experiencing the fastest gains, but eventually it'll start slowing down; don't take this as a sign to increase the dose. This is why I'm leaning towards the two week cycle; by the time your gains start slowing down, you're getting ready to go on PCT, rather than to continue taking the compound while not going anywhere with it.
So that's my take on it. Just know that all of what I typed is based on my experiences and opinions. If you have any more questions, feel free to ask!