Water to grist ratio and deadspace?

[BitterSipper]

What happens if you have a lot of dead space in relation to total strike water. I see most people add their dead space to their strike volume to get their desired ratio. But what If you are brewing a very small batch and you only need a gallon or two of strike water, but you have half a gallon of dead space. Wouldn't that throw your ratio way off?

What I'm getting at is; Is the difference made by how much water the grain is directly soaking in, or the total volume circulating the bed?

Does anyone have a good source of insight or a good explanation about this?

Thanks a lot.