Some command line rebuild numbers:
./launcher rebuild app
I did this in two consoles, triggered by pressing enter at the exact same time on the last command. I stopped the clock when the command line prompt returned from the rebuild.
Digital Ocean droplet
(different droplet, but I verified same E5-2630L CPU as in first post, 2GB $20/month droplet)
37:45 → 46:51 = 9 minutes, 6 seconds (546 seconds)
Ali Express box
37:45 → 41:38 = 3 minutes, 53 seconds (233 seconds)
So a rebuild is 2.3x faster.
I know @sam has been working on rebuild speed improvements for the last 2 days so I thought he might be interested as well.