I would say that you should be very careful with putting your Twitter-gained engineering knowledge to use in a startup. In most cases as a startup you should purposely not do many of the things Twitter does. For instance, micro services and an extremely complex distributed architecture will add a lot of overhead and points of failure when a monolith is probably the best route when you have a few engineers. In a startup implementation speed is usually the most important aspect of your development project. Hacking usually trumps engineering in terms of value-add to your infant company. You will most likely throw away a ton of code along the way in the early days as you discover your path to product/market fit. That and you will only have a handful of people actually using it. Most early scalability issues (into the 10-100k DAU range in my experience) can be solved easily by throwing hardware at the problem...

The other thing to be conscious of is the silo you live in on a team at a large company like Twitter as an engineer. You don't have to think about much more than writing code. As others have mentioned, engineering is by far the easiest challenge at a startup as a founder unless you are doing some crazy high tech thing.

All that being said, if your startup is successful and you get past the seed stage, then yes, you will have a good idea of how to build an engineering culture and use practices that are known to work at scale.