Modifications aren't usually necessary unless something doesn't work (and even then, sometimes you don't need to modify anything in Wine itself after all). You can include Winetricks as it is just a script. It would not be wise to install everything that Winetricks offers into a single wineprefix as that would totally break Wine: stuff from Winetricks should be installed only as you need them and even then care should be taken. You could, however, install everything Winetricks has to offer, then remove the wineprefix so you have a clean installation, and all installers that winetricks has used will be available in ~/.cache/winetricks. That's useful in case you ever wish to install a Wine trick without an internet connection, or "for inclusion" as you mentioned.
