Think I got it…
Added to this section:
# Get default value
set dflt [TioGetDefault 1]
set passThru [TioGetPassThrough 1]
# If the value does not exist, Just return default
if {![TioExists 1 $val $side] && $passThru == 1} {
return $val
} else {
return $dflt
}
This appears to do the trick. If there is a better way, I appreciate the guidance/advice.