I've just added a new use case to MUSIC, that I personally find useful.
The use case is taking a 'perfect' exposure bracket set from a shadow-set shutter.
I use the ML spotmeter in Ev mode to ensure the exposure in the shadow area of interest is OK.
I would normally then go to ML's advanced bracketing and set up for a 0 + ++ shot using Auto capture, which will take as many brackets as required, at the delta Ev I requested, until the 'ETTR' shutter has been reached/exceeded.
The 'downside' of using this approach is that I need to trawl through the ML screen to set things up and I can't get auto bookends, ie I would need to take an image of my hand, say, before I set ML's AB and then switch off AB to take another image of my hand.
Hence MUSIC Use Case 9.
The UC9 menu looks like this:

You can: set the required delta EV (1-4); request bookends or not, ie a dark frame either end of your bracket sequence; request a delay; you can switch on MUSIC's quick access mode, which will allow you to repeating run UC9 my simply doing a long press of the trigger button, eg SET on my 5D3 and 1-finger-press on my EOSM.
UC9 was a bit of a scripting challenge for me, so I'll say a few words here (but not on my blog) about how I 'hacked' things.
The two issues are how to make taking a bookend work with ML's script triggered Advanced Bracketing, and pausing the script until AB has finished, then switch it off in the ML menu, ready for a bookend capture.
My (hacked) solution is that, if taking a front-end bookend, I wait until the card has registered it has captured the bookend. I then initiate AB and set an infinite loop to watch to see when AB has finished, using the fact that AB completes in play/review mode.
I'm sure the code gurus are pulling their hair out reading about my clumsy scripting: but it works

BTW here is the relevant code snippet:
if use_case == 9 then -- exposure bracket from shadows-set shutter to an AB 'ETTR' shutter
local check = 0
if MUSIC_menu.submenu["Bookends?"].value == "yes" then
check = dryos.shooting_card.file_number
Bookends() -- insert bookend
repeat msleep(50) until dryos.shooting_card.file_number ~= check -- bookend captured, safe to start AB capture with correct shutter value
check = 0
end
msleep(MUSIC_menu.submenu["Delay"].value * 1000) -- user delay if requested
menu.set("Shoot","Advanced Bracket",1) -- set up ML AB for a shadows to 'ETTR' AB capture
menu.set("Advanced Bracket","Bracket type","Exposure (Tv,Ae)")
menu.set("Advanced Bracket","Frames","Autodetect")
menu.set("Advanced Bracket","EV increment",tostring(MUSIC_menu.submenu["Ev delta"].value).." EV")
menu.set("Advanced Bracket","Sequence","0 - --")
my_shoot() -- trigger advanced/auto bracketing
while true do -- wait until auto bracketing is finished: a bit hackish but works and slows you down :-)
if camera.gui.play then
check = dryos.shooting_card.file_number
end
sleep(2) -- there is a very small probability this time may not work, but a low prob I think
if camera.gui.play then -- still in play mode, so check if AB is finished
if dryos.shooting_card.file_number == check then break end
else
check = 0
end
end
menu.set("Shoot","Advanced Bracket",0) -- finished with AB
key.press(KEY.HALFSHUTTER) -- HS press to return to ML LV mode, ie from AB review screen, as AB finishes in review mode :-(
msleep(100)
key.press(KEY.UNPRESS_HALFSHUTTER)
repeat lv.resume() until lv.running -- just in case
Bookends() -- check if bookend needed
camera.shutter.ms = t_base
tidy_up() -- and exit use case 9 capture
return
end
Cheers, and stay safe and away from stupidity
Garry