Best mechanical pencil for drawing dungeon crawler maps

My teenage daughter and I have been playing a computer game from 1981 called Wizardry: Proving Grounds of the Mad Overlord. I'll have more to say about it later, but it is even more fun playing it this time than when I played it in the early 80s. One of the best parts is drawing the tricky maps as you crawl through a dungeon rendered as wireframe hallways. The dungeon has a lot of portals, hidden one-way doors, traps, and other hazards, so we have to do a lot of erasing and redrawing. We've been using the Japanese made Zebra DelGuard 0.5mm Lead Mechanical Pencil, which has an ingenious mechanism to reduce tip breakage. I just looked on Amazon and it's $5.47 and includes a bonus tube of lead. Such a deal!

https://youtu.be/oqhv_aldcoo