My problem is how far do you go with the scientific before you lose track of the art?

I have the Phil Davis book and indeed use his tube design to develop 4x5 negs but don't have access or funds for a densitometer etc. I could use the service they offer buy it seem rather expensive. I have considered the Palm handheld with his program ($120) but I cannot justify with the amount of 4x5 work I actually get round to doing (10-12 sheets per month)

For now I have to take the 'suck it and see' approach and hope to learn more about the materials through usage