There won’t be any stain left to compare
Based upon my experience with my SQ FL, I believe that if you use Whites cycle with prewash, maximum soil setting, both second and third rinse selected, cold water, Persil 2-in-one for the prewash and Persil power pearls for the main wash, with Clorox in the main wash, AND put it in with a full load of white towels so there’s decent tumbling action, the stain will come out completely. Betcha.
Usually the SQ FL waits until the main wash to add the Clorox, so the enzymes get a chance to work in the prewash before being fried with chlorine, but sometimes it empties the Clorox in the prewash, so now I wait and pour the Clorox in the drawer quickly when it starts filling for the main wash. You could also dilute it in a measuring cup and wait until 5 to 10 minutes after the main wash starts, and add it by pouring it into the main wash detergent compartment.
(I never use cold water except for tomato stains, which seem to get permanently set with anything but cold water. Cat puke/bile, though protein based, comes out with the above method with hot water and there’s no need to use cold).
Bottom line, if you know what you’re doing you can get that stain out completely in the SQ FL, but not in either the new or old SQ TL. The FL really does clean better than the TL if you load and dose correctly.
(Probably with the other FL makes, you could wash that towel alone and get proper tumbling and cleaning, since they sense the load and use less water with fewer items so you still get tumbling action. The SQ of course does not sense, just fills up all the way, and so a single item just rolls around in too much water and does not get clean.)
As always, laundry is subjective and some people out there will disagree with this, but try it! I betcha it’ll come out completely with my method.