Triggladius

As far as I understand it a soldier who had served his 25 years of service and received his donative, could be called back by a superior officer as "Evocati". I was simply curious to know how and where would these veterans would fit within the usual legion hierarchy?

Drawing the sword straight up from the right also limits your vulnerability from enemy weapons. With the scutum being slightly curved, the only way to have the space to draw your sword from the left would involve turning your shield outwards slightly, exposing your chest (albeit perhaps only a small section) but certainly enough for a spear-man to take advantage of. Drawing the sword from the right is easier to do whilst maintaining maximum protection.