"Can you cast a smaller set of rays first, and only cast the in-between rays if certain conditions are met "

Yes I can do this. But my case is really special as in basically the players have to do this by themself. As it is (also) a hacking game, meaning they have a limited scan budget and need to figure out to spend it the most useful for their bots.. but since they also want to evade projectiles and other bots, they want to scan as much as possible to not miss a threat.

So it works the way it is. Just would scale better, with better raycast performance.

I probably should have hinted more above, why my case is really special, but that was kind of my point, there are always special cases. And I do not want to limit my design, because of a bad raycast implementation.