I think this is kind of close, but I'm not sure how to talk to the field labeled index or value of the ui elements.
tell application id "com.figure53.QLab.4" to tell front workspace
set userDelay1 to 0.1
set windowName to q number & " — " & "Light Dashboard"
set show mode to false
set redsliderlevel to pre wait of cue "Slider Red 1" as number
set greensliderlevel to pre wait of cue "Slider Green 1" as number
set bluesliderlevel to pre wait of cue "Slider Blue 1" as number
set dashboard visibility of current light dashboard to true
delay userDelay1
end tell
tell application "System Events" to tell (first application process whose bundle identifier is "com.figure53.QLab.4")
set mysearchterm to "selected.color"
set listofrows to UI elements in (table 1 of scroll area 2 of splitter group 1 of window windowName) as list
repeat with each in listofrows
set rowindexcounter to UI element index each as integer
set itemsinthisrow to children of UI element each as list
repeat with each in itemsinthisrow
if count (UI elements whose value is mysearchterm) is 1 then
set therowyouneed to (rowindexcounter +1) -- because the rows index is zero indexed
end if
end repeat
end repeat
end tell
--go back to cue lab and tell it to set values using therowyouneed