Width proportions across weights

For example, the /a and /e in a monoline sans; having three horizontal strokes forces the form to widen in order to accommodate appropriately sized counters, and even out the colour. Should this then influence the proportions of the lighter weights, or should the widths adapt naturally?

For my design, I was initially going for quite classical proportions, but for bolder weights it felt right to make the widths a bit more uniform. 

So (depending on the design), what should be prioritised, even colour/width or retaining a visual consistency of widths across the family?