Touchbar and BetterTouchTool

Hi all,

I'm fairly new to Applescript, but I'm slowly getting the hang of it. Sorry in advance if I'm being incredibly stupid!
I haven't seen much mention of Mac touchbar compatibility with Capture One.
I did find a helpful post on this forum but it didn't quite answer all of my questions.
I'm trying to code a "Custom Applescript Slider Widget" in BetterTouchTool to modify either brush size or selected layer opacity, but I'm having problems finding the right way to point to these functions in the script.

I checked the scripting dictionary but found no mention of "brush". I think I've found that brush size is in tools configuration > size (integer) and that the brush size can vary from 1 to 6000. This is the code I was hoping would work, but I'm not getting anything yet.

on bttWidgetSliderMoved(sliderValue)
if application "Capture One 12" is running then
tell application "Capture One 12"
set size of tool to (sliderValue) * 6000
end tell
end if
end bttWidgetSliderMoved

Is it possible? What am I doing wrong?

Thank you.