Hi
Aslains has this option.
You can tweak it yourself if you want.
"extraFieldsLeft": [
{ "x": 0, "y": 22, "valign": "center", "h": 3, "w": "100", "bgColor": 0, "alpha": "{{alive?35|0}}" },
{ "x": 0, "y": 22, "valign": "center", "h": 3, "w": "{{hp-ratio:100}}", "bgColor": ${"def.c1"}, "alpha": "{{alive?75|0}}" },
{}
Where "h": is the thickness (hight)