>a small take home project with a reasonable due date (say 5-8 days) that is representative of the kinds of work that is expected on the job. Then, a 1-2 hour code walk through and presentation. Candidate should expect to build, run, debug and describe the code and architecture, tools choices, show source control use etc.

The problem with this is that talented developers generally do not want to work for free on someone else's proprietary software and there is a very real risk of companies trying to abuse this practice to extract free labour from candidates the closer you get to "work that is representative of the kinds of work that is expected."

I do not want to spend hours of my life on unpaid labour for a company that may or may not hire me. Give me the 45-minute algorithmic challenge that puts me on the spot every time.

I also strongly suspect your 3 month probationary period would be an effective anti-signal as well, useful for attracting desperate candidates rather than the ones you really want. You can't reasonably expect a senior engineer to jump at leaving a secure position for a 50/50 shot they might be unemployed in 3 months because they're "not a good cultural fit."