All grain water volumes

[SoMD]

Strategy for all grain water volumes
Not sure if I posted this correctly the first time....
I'm about to venture into all grain and have been doing a lot of reading about sparge volumes, evaporation rates, losses due to equipment, grain absorption etc. However, while these calculations seem important, I was thinking of a more intuitive approach: I start with the assumption that the goal of the mash/sparge is to extract a given amount of solubles for a predetermined batch size. So the main objective is to get the solubles in the BK and not worry about sparge volumes.
So, I was just planning on a 1.5 qt/lb mash and fly sparge until I hit 2-3 brix (@ 1.010 gravity). That way the solubles will be extracted while staying away from tannins etc. Also, if my target batch size is too low after boiling, I will just add water to the fermentor since I will have recovered the correct amount of solubles per the batch size.
Seems the focus should be on what is in the water rather than the amount of water.
Am I crazy??? I apologize in advance if this has been covered....

 

[Hopper450]

I suspect people more commonly have issues with undershooting the gravity they are aiming for rather than overshooting it or boiling it down too much (though I've managed to do both so far). I believe all the things you mention are just factors you can look at if you aren't getting the gravity you want at the volume you want with your particular system and technique.