Homebrewing - Beer, Mead, Wine, Cider

the finings will clarify for you (lol)

in all seriousness, you can't count on 12% to be where yeast dies due to alcohol. Some yeast tolerates up to 20%, and even strains that are marked to 12% could overperform a bit. What that means is, if you follow these directions, you very well could wake your yeast back up and end up building pressure in the bottles. This could cause them to explode and fling mead everywhere (hence, painting your ceiling). The only ways you can count on to be able to backsweeten without risk of reactivating the yeast culture are chemical (potassium metabisulfate and potassium sorbate) or pasteurizing before backsweetening. Since you said you don't want to go the chemical route, pasteurization is the best way to go.