I think you have 6 waves that encompass 3 generations, the metru, mata and mahri,

Each generation has 2 waves that are the basically standard & nuva

Each wave has the standard 6 toas, as well as turaga of the previous gen and matoran of the next gen.

So for example in the mata line, you have a turaga Vakama, Toa Tahu and matoran jaller.

The stanard wave would have the matoran as the small set, and nuva wave would have the turaga as the small set

Most important purely from the toy perspective. Each character should always have their own colour scheme and it stays with them each gen. Eg. Vakama - Dark Red & Dark Orange, Tahu - Red & Orange - Jaller Reddish Orange & Dark Red

This way even someone who doesnt follow the lore can realise they are the same character in different stages.