I have seen through the years individuals run header tanks on the N5 thru N5c series Helis. I will say there are those that do and those that don't (myself being one that doesn't) most are weight conscious when it comes to the Helis and capitalizing on the fact that the N5c is the lightest 600 class heli on the market today. You do gain that little extra time in the air. I think any brand would be fine, just make sure the mounting band is high quality and a snug fit, some of these tanks don't fit well in there mounting bands and rattle which will cause Gyro issues due to vibration.
BR,
Kevin