It's probably a full circle, but because of ooze and retraction, the extruder may not always immediately start laying down plastic for a distance. If you're seeing 3/4 of a loop, it's probably still priming for the first 1/4-turn.
The skirt's really handy for making sure extrusion's (and first layer adhesion) is going the way it should. I usually use a 3-loop.
Skirt is controlled in the Advanced settings, on the Expert tab in FLUX studio. The parameters you want are:
skirt_distance (distance from the model the skirt is laid down)
skirt_height (how many layers the skirt extends up)
skirts (how many loops the skirt consists of)
In Cura, similar options are on the Print | Structures tab. In Slic3r, Print Settings | Skirt and brim.