I don't understand the HP-50g, what am I missing?

[Steve Simpkin]

Since you are familiar with the HP-42S, I would recommend looking at the book, "HP 41/HP 48 Transitions" by William C. Wickes. William C. Wickes was the project manager for the HP-28 and HP-48 calculator projects and is very good at explaining how RPL works and the reasoning behind the evolution of RPN to RPL. While it doesn't cover the HP 50g, I hope it may make transitioning from RPN to RPL a bit easier.

A PDF of this book is available here:
https://literature.hpcalc.org/community/...itions.pdf