I have a measuring wheel. Takes a couple of minutes to walk and measure.
Then I price by the square foot.
You take more time you need to get paid more.
This is why you don't have partners.
When you have neighbors that live side by side. One has a 10,000 sf lot. The other has a 11,000 sf lot. There property is different and they need to be charged different. Even if it takes you only 2 minutes more you should get paid the $2 more or whatever the amount comes to.