Not much. The F-117 is stealth mostly due to shape. The B2 stealth is mostly due to materials and construction techniques. You can run optimization routines to reduce scattering, but it’s not going to be huge improvements

This is a good book that discusses several techniques:

https://www.amazon.com/Radar-Man-Personal-History-Stealth/dp...

This is a good, lite technical read for those interested in stealth.

https://www.amazon.com/Radar-Man-Personal-History-Stealth/dp...