When creating a new focus for The Strange, do I need to fill the 6 levels for it or could I leave some "blank" levels?
One option is to nerf an ability gained at a given tier. For example, taking an ability that you've called "Packs a Wallop" and it originally allowed an attack to do +3 damage at tier 2. You could lower the damage to +1. Then at tier 4 the character gets "Packs a Bigger Wallop" which adds +2 damage to the tier 2 ability. So at tier 4 they do the original planned +3. This seems to fit other foci (there's one in particular in the Cypher Core Rulebook, but I'm drawing a blank).