While making a small experiment with the Q2Launcher, I've found a way to use it on Quake 1.

1.Copy both Q2Launcher.EXE and Q2Launcher.INI to Quake 1 folder
2. Edit the Q2Launcher.ini and make some edits to make it run Quake instead (optionally, mods as well)
3. Make a shortcut of Q2Launcher then go to Properties.
4. In a Launch Options you need 10 numbers of the input before putting Q2Launcher.ini. You can get it by checking out it's name of the dll/ico/info file.

If for example i have goggame- 1231245654.ico

I just type "1231245654 Q2Launcher.ini" so i have:

D:\GOG\Quake II\Q2Launcher.exe 1231245654 Q2Launcher.ini

After that press OK and poof. You can now run Quake 1 via Quake 2 launcher.

Clever! :)