Honestly, and with all respect intended, 12 weeks of a 17aa - as you put it - is not as bad as everyone makes it out to be. There are numerous other medications far more hepatoxic to the liver that docs will prescribe without telling you to take this or that. The liver continues to function as normal even if 70% + of it has been damaged and can repair itself back to 100 % quite efficiently. Although I am not recommending a 12 week course of winny and dbol to everyone out there (again varies on dose) - it will, in most cases, not be as detrimental as everyone will tell you - mostly from what they have read others tell them.
I am soon to be ending a cycle started off with 100mg winny a day (along with test) went down to 50mg a day while running 20mg dbol alongside. Stopped the winny after about 5-6 wks and went on dbol at between 50-60mgs a day. With a liver supplement (detoxifying thing) and 8 litres of water a day, I am not experiencing any problems.
Could just be me - but a lot of people say what they have heard, not what they have experienced.
Around 10 years ago people would run winny for 12 wks + (vets on this board) with no problems. I am certain some people run it for longer although I am not recommending or suggesting to try it.
A lot of water, normal milk thistle, a multi vit and mineral should ensure normal function if the substances are only used for 12 weeks. Of course, nothing more safe than a relatively cheap test to confirm half way in to the cycle.