Hi @sci9249, I am sorry I just saw your message and certainly do...

Hi @sci9249, I am sorry I just saw your message and certainly do not mind at all mate.  I remember the day that I lost the TF feed from may main broker and was given the message that I need to pay for it in order to keep receiving the free live feed ...that was obviously before the change but must have something to do with it.  Now of course I watch the RTY instead although I have not traded it. Yes they are the same thing with a different provider although there was a transition that gradually took place with increasing volumes on the RTY.  The RTY contract started trading on 10 July 2017 and I never saved any TF charts.  Here is the continuous RTY chart dating back to its inception.

From CME: Transitioning E-mini Russell 2000® Positions from ICE to CME
10 May 2017 By CME Group Topics: Equity Index
On July 10, 2017, CME Group will launch the E-mini Russell 2000® Index futures and options suite. CME will have the exclusive rights to list futures and options on the index; however, at the time of the launch, the futures products will be dually listed by CME as well as by ICE for a period of time to facilitate the transition of open interest between the exchanges.1
Please note, the positions will not be moved to CME without client action.

The RTY replaced TF but that does not give me confidence to answer your question about back testing anything other than the RTY.  Of course depending on what you're doing, the changeover to new contracts every quarter might impact what you are doing and if you have any questions about that let me know.