Hi Luos,
Thank you for reply! Before I accept your answer, please give me some time to do a bit of research on the matter 
Do you have any additional links where I can read a bit more about things you’ve mentioned? I honestly tried to look it up, but info seemed too scarce for me. I hope to have more details on:
- Mobile platforms specifically don’t like to have a lot of instances? (this is news to me)
- I’ve read that Static Switches causing “Shader Explosion”, is it what you referencing to as overhead? I couldn’t find any technical info about it.
General approach “make as many as you need” feels a bit carefree, but you maybe right
But doesn’t engine optimize loading of the same shader? In case it does, are the gains that negligible?