I've got some pieces of his mails from Paradox forum. They are much more informative with numbers than response I've got. I'm especially interested in the state of the potentially opposing such a drive Soviet armies, since the battle of Smolensk was coming to an end and the Soviets were...
Mainly about his upcoming volumes and the contents (he's working on Volume V right now and he shared with me all the contents, which aren't available on his website), his other plans (addendum on logistics), his response to the TIK's video, his current occupation and a bit on Lend-Lease effect...