Don't worry about speed, it is not the goal. I myself tested it with 5/6 of the hard options and won by month 7, without hurry. The option "invaders move twice" is possibly doable but I don't have the patience to test with, as turns would take up to one hour. The setup is done in such way that you can combine easy with hard and get game more fun.

About tew 4 version, I didn't yet send both tew3 and tew4 updated to mapsforheroes so no one has them (except you cuz you were playing)

Now that I am done, I will send them next days.