Different manufacturers supply different pad thicknesses for different compounds, so the configurations are endless. You should be able to ask Mr Google for the original spec for your pads and see how it relates to what you have remaining.
The 50% standard benefits heat dissipation under heavy braking. You can get more use out of those pads for your daily street driving. The thicker pads are also easier on your rotors as they are less likely to warp them from heat concentration.
Yeah. Worth mentioning: If you’re concerned about throwing out perfectly good pads just because of DE rules… don’t. Keep them. Put them back on after the DE is over and keep using them. They’re fine for the street.