gentoo boots! 
hm, no graphical interface yet, and i haven't set up a user yet either, but maybe that's the finalising step, let's see (can't work from the laptop itself any more now tho)
wireless card showed as disconnected, and i don't have an eth port. so i rebooted the live environment again, changed the make flags to use only half the threads (compiling may take longer, but hopefully won't drain more energy than the charging provides), and it's now installing the kde meta package. seeing how it's late, this may very well be the end of today's adventure for this. i have no idea if kde will "just start" or if i need to do more, but we'll see when we'll see 

@ilja You need something that starts it (or you can run the commands manually if you really want to)

I use sddm

beware though: compiling kde-meta will take forever even with a decent machine if you don't have USE="-webengine"

@eal ah, im assuming i do not have that flag  but it's running now so ill just let it be :) if it's still running by next weekend, ill reassess my strategy