It seems like the strategy tool is no longer needed.
If I remember correctly, its purpose was to help determine how many laps could be performed on a specific amount of fuel and tyre selection.
The new iGP now accounts for this in the next race page and in the race viewer.
Although the prediction in the new iGP may still be inaccurate, it will be improved to project a better prediction.
We have Ricardo Patrese to thank for contributing his tool --- it may have served as the inspiration and need for the creation of the prediction feature available to us today in this version of iGP.