Chrome is too, they only open the chromium core.

No , Chromium is almost 100% chrome , just without Google Service specific features .

Features like the updater / appmanager, which is borderline malware and one of the reasons I uninstalled Chrome (and boy did it take some effort). Regardless, Chrome is not fully opensource, so there is no way to "calculate" the % you mention. Google might be running a bitcoin miner in Chrome and you would have no way of knowing.

The degree of trust required to run Chrome is equivalent to the one you need to run Vivaldi; the only difference is who you trust (Google vs a bunch of ex-Opera developers). If you don't trust anything that is not opensource, you shouldn't run Google Chrome - you should run Chromium or Firefox builds published by trusted parties.

How can I run chromium as a daily driver on windows? What about automatic updates?

Choco packages chromium nightly builds for Windows.You could automate 'choco upgrade chromium -Y' (Daily snapshot builds).

Otherwise: http://chromium.woolyss.com/#windows

Which packages http://www.henrypp.org/product/chrlauncher in the portable edition

Try Brave then? FOSS, based on Chromium, created by Brendan Eich.

Wow, that is pretty gross, makes me wish chromium was GPL.

But that would prevent Google releasing the closed source Chrome.. And if khtml had been GPL apple couldn't have released the closed source Safari browser based on it - which would have meant that webkit might never have become mainstream - and chromium probably would have never even existed.

This isn't the entire source code. It's just the changes that they've made directly to Chromium. They can still bundle all kinds of closed-source stuff alongside that, just like Google does with Chrome.