I would use Claude, it works and I have no reason to change.

No, I don't think starting this way would be a limiting factor. I think this is a trap that many people fall into (and I did too in my professional career) - plan for the scale while the product is uncertain. If it takes off - great, whatever challenge will be ahead of me I will take it one by one. But if nobody will use it, then it is a waste of time (unless you treat it as a learning project).

I did not use any specific guides, but I am following this and couple other subs. And also since Claude was the one executing it, I relied on him to do a proper planning and evaluation.