Which is best for scalping?

Is it instrument specific? Or does it matter?

ES? YM? CL? 6E?

I have a Zenfire feed and Ninjas representation of that bid and ask data is not very good to say the least

tulanch 

I have a Zenfire feed and Ninjas representation of that bid and ask data is not very good to say the least

What is wrong with Zenfire and Ninja tickcharts?

they do not match up on refreashes

there are a number of threads that go into detail about this

Zen is an execution feed, it is not a data vendor feed.

Zen, just like TT Feed will drop ticks and/or bid/ask updates if it feels it needs to do that in order to prevent delays that would cause you to lag.

There is nothing wrong at all with Zen, just that people don't understand what it is & end up using it for something it's not built for.

I think Crude oil.
because, i think crude oil has biggest volatility in your list.