I used Nizoral 2% for about 6 months. I had excessive scalp sebum (it got worse when I started finasteride) so I applied nizoral every two days, instead of the every 3 or 4 days indicated on the box. About two weeks later I realized my sebum reduced drastically so I lowered the dose to two times a week, eventually applied it only once a week.
Sides: Had minor discoloration. I have black/dark brown hair for the most part, and some parts looked reddish and also got some gray hairs (never mind it though). My hair started to shed drastically around the six month mark, which prompted me to stop using it even though I can't assure it was nizoral causing it.
Conclusion: I'm very positive I recovered the shed hair once I stopped, and also the six month mark worked just fine for me because 1. I haven't got the awful scalp rash I had before using Nizoral and 2. If I ever got back to excess sebum I would use nizoral again since nothing considerably bad happened during my usage.
Edit> Ah, typical of me, I didn't answer anything you asked for.
1. I don't use conditioner. I only use natural shampoos, with the least of chemicals and every time I used nizoral it was just the nizoral.
2. 2% is much more stronger so it isn't suited for delicate scalp skin. The reason I used it was because my problem was rather severe. Like really, really painful rashes so I never even thought about getting the 1% nizoral.