I marked my wooden mash paddle with a wood burner/soldering iron. One side for MLT strike volume, one side for HLT sparge water volume. I didn't feel like adding an additional tool to locate on brew day. 98% of the time, i.e. normal gravity range beers, I don't change my strike/sparge volumes. I just let my liquor:grist ratio vary.
Boil kettle volume for a 90 minute boil is the edge of the compression fitting on my whirlpool arm.
You can see the mark under the top hole in the paddle.