With the landing page alive and kicking, I've sold another 10 additional copies of REBASE, resulting in 40 total sold copies two weeks after pre-sale launch.
I've also fine-tuned the landing page over time, learned a few things here and there to make it more effective.
Some things I've learned:
Find the updated landing page at rebase-book.com
In addition, I'm aiming for writing/finishing one to two chapters every week until the first release. So far this has worked very well as I've finished 3 chapters by now.