You are correct that heavier bullets in a given caliber usually use slower burning powder.
Burn rate is measured by a test done called a "closed bomb test" a small amount of powder is contained in a closed cylinder and ignited and the pressure and speed of burning measured. Really complicated stuff. Only the big boys have the equipment to do this.
All (well most anyway) good reloading manuals have a table that shows burning rate compared from one powder to the other.
Really the best thing to be said for burning rate is USE THE CHARGES RECCOMENDED IN A GOOD MANUAL!