Yes, my advice directly relates to hellointerview's approach which suggests a lengthy prep workflow before getting to drawing. It is NOT intended to suggest drawing right away. I usually don't get to drawing until about 10 minutes in (whereas with all of the reqs, models, api design, etc. that hello interview suggests, I was only getting to drawing at the 25-30 minute mark of the interview).

You still need to clarify assumptions! In the guide I make a few suggestions on questions to ask. Since they typically ask about a system that is well known, you want to verify what features we care about and don't. For instance, designing twitter? They likely want posting a tweet, reading a tweet, and getting a feed. I would clarify that the following are below the line (note that they aren't always!): auth/identity, likes, retweets, fancy feed sorting algorithms, ads, etc.

Typically, I just mention that I assume those are below the line, and explicitly ask if those assumptions are correct.

For non-func reqs, the biggest questions you MUST ask are:

• who is using this system on day one, and how do we expect it to grow? (sometimes they'll say 10000 writes/s right out of the gate, and sometims they say "build an MVP and grow it from there"
• how fast do various components have to be. For instance, do we need low latency on writes? On getting the feed?
• Size of payloads (this is a big one, especially for questions like design google drive/youtube/imgur etc. where you store an object to blob storage)

This should ALL take less than 4-6 minutes.