Follow these guidelines and you'll be surprised how far you can go.

https://google.github.io/eng-practices/review/developer/smal...

So you want code added in 100 line sections behind one feature flag which we then suddenly turn on?

Isn't that exactly how Google's latest big cloud outage happened?

EDIT: referring to https://news.ycombinator.com/item?id=44274563

I should add that the idea complexity relates to LoC is also nonsense. Everyone that's been doing this for a while knows that what kills people are those one line errors which make assumptions about the values they are handling due to the surrounding code.