There actually used to be a mod that just added sulfur ore to the game, but I am unsure if it was updated to 1.1.
From what I understand you're after, you want to install this Library and the Ores mod ONLY, don't install MCI.
Then from the mod options page, tick the Sulfur ore only. This will cause it to show up on the new game menu's list of resources for you to set it's values, however, do not worry if you want to load an existing game, as it will spawn with default values when you explore.
Sulfur does not spawn in the "Starting area", so even if you do start a new game, you'll have to go explore to be able to find it.