Accordion notation for beginners

[Volker Paul]

Much accordion literature I got from my accordion school
is in a format that, for lack of a better name, I call it x/ ("x-slash") 
notation. The left-hand staff consists of a single line. The bass is shown by a 
diagonal cross (such as noteheads.s2cross), the chord by a diagonal line (such 
as noteheads.s2slash), bass and chord together by a cross with one double line 
(from bottom left to top right; noteheads.s2cross and noteheads.s2slash could 
be used on top of one another, but don't fit together optically), quint (fifth) 
bass by diagonal cross in a circle (such as noteheads.s2xcircle; for C, quint 
bass is G, for G it's D and so on).

I described this in more detail, with examples, on my homepage:
http://www.v-paul.de/lilypond-acc.html

I wanted to write songs in this notation but I found it difficult in Lilypond.
With some effort I finally managed it. The result is a template that 
I published on my homepage. Now for my questions:

    * How widely is this notation used? Is it only for beginners? Which 
notation is used for advanced accordion players? AAA notation?
    * So, does it make sense to further develop a template for this notation?
    * If so, is this template described here a good start? Are there different, 
better approaches?
   * Is this template worth being included somewhere in the 
Lilypond documentation? 
On my homepage, I will keep it anyway.

Cheers,

Volker