50g questions (dispatch, menu number, CODEM)

[BINUBALL]

I have two questions about hp 50g. Here are the questions.

1. Finding menu number using only hp 50g itself
Of course, I know there is menu number in AUR appendix H. But I'm curious if 50g itself can find menu number. Using trial and error costs much, much time.

2. Dispatch more than 5 objects
On sysRPL programming we can dispatch number with command like CK1&Dispatch, CK&Dispatch0.. and more. My major problem is, how to dispatch more than 5 objects. Binary Integal can be up to only # FFFFFh. So It may be impossible.

3. CODEM
CODE - ENDCODE syntax used for inserting saturn code. However some source code I've seen contains CODEM - ENDCODE. Why are them use CODEM and how to compile code which using CODEM?