[New technic launcher not saving settings and losing custom modpacks]

Make sure to run the technic launcher as an administrator, so that it can save settings/files to its install directory

Right click the shortcut, select properties. Near the bottom click advanced, and tick Run as administrator.

--edit--

not sure how to do this in macOS, or if it would even be a fix.. sorry

[Voltz Seeds]

yes, the minecraft world generator works the same, but each modpack also adds its own parts, like tekkit volcanoes/oil or the bunkers in voltz..

i found a basic voltz bunker seed:

ignoramus

dont ask why i chose to try that, i dont even know..

spawns you in a jungle biome with a cobblestone bunker, not much in it, but its a good starting place and has some redstone/mossy cobble

haha lol.. i'm the ignoramus... thats a normal minecraft thing lol.. guess i haven't played with that many 1.4.x seeds yet.. *facepalm*