Hmmm, so I can’t glue tubs today with my usual facility- I have a work stopping injury. I’ve injured my right forefinger which is my tub glue spreading finger. The left fore finger is too stupid and the one I landed up using, my right middle finger, is too fat. That right index finger is just the perfect curvature to spread Mastic one (my tub glue of choice) in the well of the rim.
Now you know how to identify a wrench who also does fitting- slightly longer index finger nails, and glue all over their dominant index finger.