Groove-to-Band Length Ratio (GtoB)  is a way for the computer to decide how big to make the grease grooves.
If the groove is very long relative to the depth (say GtoB = 1.5), the lube may refuse to stick to the groove, creating problems at the reloading bench.
It is very desireable, from the mold maker's point of view, to avoid grooves with a "V" shape, because the sharp corner on the "V" is prone to have burrs and does not facilitate fill or release. Instead, please select a design that has a flat at the bottom of the groove like "\_/". It doesn't need to be a big flat, as long as the flat is there.
Please do not attempt to imitate the Lee tumble lube design. The Lee bullets have shallow, rounded grooves which this program will not create. Furthermore, any grooved bullet can be tumble lubed.
When the paper patch mode is chosen, the program will draw a bullet with small grooves, but the mold will actually be cut smooth. This is due to program limitations. Please note that conventional grooved bullets can be paper patched and may shoot better anyway.