Been mixing mortar like I'm baking a cake from a recipe my grandma lost, just vibes and whatever ratio feels right. That 1 to 4 thing is wild though, your old boss basically taught you to crumble those old bricks on purpose. The lime ratio really does matter on the soft stuff because those old bricks need to move a little and the hard mix locks them up, then the freeze thaw does the rest. Sounds like that grandpa knew what he was doing keeping that manual around. Might have to dig through some old books myself before the next repoint job.