I am a strategist at a smallish boutique quant investment firm. This is how we think about hiring a junior person. It's not all that different for a more senior person, but actual development experience would likely be more important, we would expect more contribution sooner from a more experienced person. More senior jobs also might have more specific responsibilities and therefore require more specific knowledge of technologies, etc. Many junior analyst roles support the team as a whole and there is less concern around experience with specific technologies, typically.