The relationship between stroke weight and letter width

What is the ideal balance between stroke weight and letter width when designing for maximum letter legibility? With variable fonts, such a question is more relevant than ever before. Could it be that there is an optimal stroke weight independent of point size? Is it essential to maximize the size of the counters when adding stroke weight? Is stroke weight in fact unimportant, while letter width has the greater effect on legibility? Or is the best way forward to add as much stroke weight as possible, as the effect of letter width is insignificant? These questions have been investigated in a new experimental investigation of single letters presented as quick exposures in the peripheral visual field.