Ratios are usually noted as (grams of coffee) to (grams of water), for example 1:16. That’s fine if one is usually brewing the mostly the same amount of coffee on every recipe, but a bit backwards if it comes to the situation of figuring out how much coffee to grind to serve some guests. In that case, measuring ratios as (grams of coffee) per (liters of water) is more intuitive and usually results in simpler math.

For example, the 1:16 ratio is equivalent to $\frac{1g}{16g}\times\frac{1000g}{1L}=62,5g/L$. The 60 g/L ratio is equivalent to $\frac{60g}{1L}\times\frac{1L}{1000g}=\frac{1}{50/3}$ which is a ratio of 1:16.6. The 1:16 notation makes it easier to calculate the amount of water to use for a recipe, while the 60 g/L notation makes it easier to calculate the amount of beans to grind to get a certain amount of brewed coffee.

Changing ratio should be one of the last variables to adjust when working on a recipe, aiming to change the Brew Strength only and not the taste. That’s because if a brew is weak and under-extracted, adjusting strength first (reaching ideal strength but still under-extracted coffee) will still require an increase in Extraction Yield and the means to do so almost inevitably also increase strength, thus overshooting the strength adjustment just made.

Ratios vary across Extraction Methods. Infusion methods usually benefit from a bit more coffee than percolation methods to reach the same strength because not all of the water used in percolation participates in extraction for the whole time. Good starting points would be 75 g/L for infusions and 60 g/L for percolations, but these are mere suggestions that should be adjusted to each ones taste and the coffee specific characteristics.