Q: Which is the best colour for a lens?
Unfortunately, there is no single answer to this question. Everyone's eyes are different and what suits one person will not suit another. This is why lenses come in a huge array of colours and you may need to experiment before you find the right one for you.
It is also likely that you will need more than one lens to cope with different coloured targets, backgrounds and light conditions.
Q: Should I go for a dark or light lens?
The basic rule is that you should use the lightest lens possible that prevents you from squinting.
When you shoot you want as much light in your eye as possible, this will allow it to focus better helping you to see the target quicker and clearer. However, you do not want too much light as it can cause eye strain and fatigue.
Q: What's the difference between Pilla Outlaw X6 and X7 glasses?