As a kid sized jug hold, these will feel big and positive. Children will be able to hold on to these easily on vertical walls which makes them an excellent choice for traverse walls. On a 45 degree overhanging wall, they will be challenging, but not impossible for children.
For the adult sized hand, let the walls get steeper because this is the type of hold you want to train on for steep wall thumb catching action and forearm workouts. I wouldn't say these are warm up holds on steep walls, but I will say they are on my wall. I get on them right after I’m warmed up.
You can expect a mini jug out of this set that has thumb catches from the divot design. There are even a few full on jugs in this set.
You could use these on roofs but only for advanced climbers.