Since having Novation Impulse I've been desperate that there is no way to use it for specifying which tracks to record.
So as Live9 scripts are now opened I decided to try modifying the scripts.
I have no idea of how to program Ableton and python

So far by analyzing the scripts I've added an option to swicth on or of overdub button on Shift+Rec.
Yes, did you know that Ableton scripts can use Shift button? for example in arrangement view, shift - forward sends you to the last known point and shift+ back send you to the beginning.
So my hope is that I could make recording the tracks you want and I think we can put this on shift+mute buttons. But this all requires extra work and extra investigation.
mostly works for Live 9 and Live 10.
Enjoy!
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UPDATE
here is the latest source
https://github.com/maratbakirov/Ableton ... n_Impulse2
to download - go here
Ableton 10:
https://github.com/maratbakirov/Ableton ... /_releases
Ableton 9:
https://github.com/maratbakirov/Ableton ... /_releases
Novation_Impulse2_9_1.zip is for older versions
Novation_Impulse2.zip
is for newer versions
UPDATE2:
current version
the functionaliity is kinda stabilized. I've done all that was easy
It might not work well on Novation Impulse 25 as the original scripts were recreated not very well and I do not have impulse 25 to test the stuff.
I think the script is powerfull enough already.
Current Features
Shift + Mixer button 9 = Automation record on/off
Shift + Rec = Metronome on/off
Shift + PLay = Undo
Shift + Stop = Stop all clips
Shift + track mixer button = rec this track..
Mixer button 9 = OverDub
Shift + Clip buttons are now clip stop.
new from 2014.04.12
Shift + Ffwd/Back buttons are now device scrollers - they pick next or previous device in the chain.
new from 2016.10.02
Now if the only one track is armed, it automatically gets selected
new from 2016.10.16
Shift + Loop button enters "alternative mode". for now the only difference is that the mixer buttons are permanently assigned to "ARM" mode (like shift is always pressed).
this helps with changing instruments on the fly during performance when only one hand is available.
Planned features:
add support for toggling arrangement overdub