Sequence string

I'm working on some hackable code for testing out ideas about tuning. I have
no intention of trying to replace Scala at any point; this is just meant as
a supplement for my own purposes - and if there's interest I'd like to
distribute it. Some input is desired about something here. Right now, I'm
supporting homophonic notation of the following sort:

"6&14 3&11 0&6&14&19 0&-8.75&4.5 0&6&11&1/2&3/4 3 6 11/5 7/4 3/2 5/4 6/5 3 6
0 0"

Not that it matters, but the above example string was set in 19-EDO. In the
above, "&" designates that multiple notes are played together, so e.g. "0&6"
is the dyad consisting of degrees 0 and 6 (tonic and mediant of the major
scale in 19-EDO). You'll notice that note numbers can also be negative and
fractional. Written ratios are always interpreted as interval ratios (not
note numbers); numerators and denominators can be fractional as well, but of
course not negative.

Now I am adding in chords written in identities and am wondering how to
interpret the root and octave of the chord. For example, an octave-proper
"5:7:9" might be considered for the purposes of the program as rooted at
1/1, or 5/4, or 5/1. Also, it would be nice to be able to mark chord
inversion simply without writing a new set of identities, but I'm not sure
how to do this for something like a hexad. There are probably other things
I'm not even aware of. I'd hate to code this up and then realize it could
have been done it better.

Another notation I'm thinking of is "[]" to shift 1/1. Something like "0&6
[11] 0&6" would mean "play tonic and mediant; shift so that 11 (the
dominant) becomes tonic; and then play tonic and mediant again in this new
position". (Of course, it would also work on ratios.) The 11 would not be
sounded,

What sort of sequence string would be most useful? Could someone perhaps
provide an example of this sort that they think would work well? Feel free
to change anything I've already done; e.g. if you hate my use of "&", change
it to whatever you like. Right now I'm not interested in adding notation for
rhythmic variation or anything like that but am currently just using this as
a homophonic tuning tester. Still, feel free to mention any extensions you
think would be useful, be they rhythm, timbre, glissando, etc. The guiding
principles are simplicity and ease of use.