Which is more effective shampoo for Androgenetic alopecia Ketoconazole 2 % vs Piroctone olamine 0.5 % vs Zinc pyrithione

Shampoos are not the primary treatment for male balding. Patients who are search for the right shampoo are taking the wrong approach. But there is weak evidence for benefit for ketoconazole and zinc pyrithione. The others have no evidence whatsoever in the treatment of male androgenetic alopecia.

none of these are backed by solid evidence. I would suggest you invest the money you will spend on these on a  consulration with a  hair transplant plastic surgeon who can give you advice.  

There's no way to say which will be more effective. I highly doubt either of these will make a significant impact on your alopecia, but really the only way to know for sure is to try them and see if you notice any difference. If you aren't already, I'd recommend you seek out more established treatments and focus on those.

Androgenetic Alopecia is caused by DHT binding to the shaft of the hair follicle and essentially starving it of the nutrients it needs to absorb from the blood stream to survive.  Anything that can actually penetrate through the skin to impact hormones within the body are required to be regulated by the FDA.  There are no FDA regulated shampoos or anything that can be purchased without a prescription.  Therefore it is not possible that shampoos can impact or cure Androgenetic Alopecia.
Its important to use facts and logic when assessing any treatment for any medical condition.  don't waste your money on treatments that are ineffective.  The ONLY effective treatments for androgenetic alopecia or any form of hair loss must be prescribed by a doctor.  Please go and see a doctor who specializes in hair loss. 
There are prescription treatments available which can stop your hair loss and regrow your own hair without surgery.  Search for hair regrowth specialists and you should find some.

There is no shampoo for stopping hair loss because of AGA. But procapil and minoxidil containing serums work well on  AGA caused hair loss. PlantStemCell Technology Malus Domestica (Swiss Magic Apple Stem Cell) , AnaGain, GSP-T
(Procyanidins + Tocopherol), Avenacare
(Oat Beta Glucan) containing serums are also effective on hair loss.

The approaches your outlined are not predictable in terms of the results you need to see to treat this condition