I would definitely choose the E-series. I assume that the tank design will be submitted early enough to allow for the beginning of mass production and for several Panzer Divisions to be equipped with these tanks by 1941 before Operation Barbarossa.
As much as I would like to choose the E-100, it seems to take too much fuel and is too slow, even if it is nearly invincible.
So I would choose either the E-50, the intended replacement of the Tiger 1 or the Panther, or the E-75, the replacement of the Tiger 2. However, these units would have been much cheaper and easier to produce, getting rid of much of the noncombat problems the earlier tanks had.
Honestly, I think Germany, combined with good decisions (such as not declaring war on the US and having a better strategy), could have won the war with the full group of E-series tanks. I am unsure though why the E-10 and E-25 would need to exist, as both serve the same roles. I think only one of them would have been good enough. Similarly, I think only either the E-50 or E-75 is necessary. The E-100, though, as good as it is, would not have been practical.
