I've only used a few stock coils in my protanks 1 & 2, because they seemed very inconsistent to me. One would last two weeks, the next only two days. You can rebuild your own coils with better quality and performance, cheaper too, with a little patience. So don't throw away any of your atomizer heads, in case you decide to give rebuilding a try. I could tell you how I make my own if you're interested, its also talked about all over the place here and youtube has some great vids too.
As far as the juice goes, I don't like tobacco flavors, just menthol/fruity stuff here, so I don't know about that. I did find that 80/20 pg/vg juice was too thin and constantly flooded my protanks. I switched to 50/50 and haven't had any issues since, it's wicking great for me with ZERO leaking...