How does the output signal change when the Cytosol reaction volume is increased by 1–2 µL?

We’ve been asked the following question and suspect it will be of interest to others:

”I know a couple other people are struggling with there being too little room for water/additives in the current cytosol reactions, especially for sensors where I’m now dealing with up to 4 additives. Has anyone thought about or tried adding an extra 1 or 2 ul of volume to the 10ul reactions, and how much that would decrease signal compared to the optimized 10ul reaction?”

How are researchers managing reaction volume constraints when incorporating multiple additives, and how does the output signal change when increasing the reaction volume from 10 µL to 11–12 µL? Are there any data or observations available on this?

I haven’t tested this yet, but I suspect the output signal could change by at least 5–10%, since adding a couple of extra microliters may alter the effective Mg²⁺ concentration which is a parameter that Cytosol reactions are particularly sensitive to.