How many Reflection Probes needed?

I’m trying to optimize reflections in my scene so I’m wondering what would be the best and the most performance-friendly way to handle hundreds of glossy transparent bubbles scattered all around the level? I want to use some lowres exr cubemap for reflection to exclude any realtime reflections as it’s not necessary for me.

I want reflection on those bubbles to be absolutely the same so can I use only one Reflection Probe for all of them? Will it matter where I place it then?

No ideas? :frowning: