Were your other attempts also traditional (i.e. only honey, water, yeast, nutrients - and no fruit or other adjuncts) meads? I ask because honey-only musts can often be more difficult to ferment to dryness than those also containing fruit or fruit juices. The various compounds that exist in fruit juice often provide lots of pH buffering capacity, so although they are typically acidic, the pH of the fruit must doesn't change much during the course of fermentation. Since there is very little in the way of buffering capacity in honey, oftentimes during primary fermentation the pH of the must will drop significantly - sometimes going low enough that the yeast are really stressed. That can cause a fermentation to slow way down, or even to stall out. If you have a way to measure the pH of the must, I'd suggest doing that first - even before pitching the 1118.
And yeast hulls, sometimes called "yeast ghosts," are the cell walls of dead yeast that have been processed so most of the internal guts of the yeast have been removed. They are useful sometimes to get a stuck fermentation re-started because the cell walls provide binding sites for chemicals that are yeast toxic, and those dead cell walls attract and hold toxins that could otherwise interfere with the active yeast. Additionally, they can supply slight amounts of amino (aka organic) nitrogen compounds which living yeast can utilize late into fermentation - unlike the non-amino nitrogen that is supplied by chemicals such as DAP.