I would like to thank everyone who responded for taking the time and explaining ways how my goal can be accomplished.
I did look into how a patch may be written, but basically, in my case, I just needed to tweak a couple constants in the Rasmol source code. I haven't educated myself on how to patch or deal with patches yet, and I'm sort of pressed for time, so I just tweaked the source code and installed the package by performing ebuild steps manually. While that may not be a satisfying method in general, my task was very simple, and this did the job quickly. If I had a more massive task, or series of tasks, then I'd certainly look into how to deal with patches and overlays. Again, thanks to this wonderful community :-) -Denis
