I really only do large beers and did a nice chocolate/coffee stout that came in around 13%
Your main concern should be oxygenation prefermentation then using some type of step addition of simple sugars to get you to where you want. Give the yeast a few days to work through the more complex sugars of the wort, then start with sugar additions.
With really large beers, you're going to been to re-oxygenate around day 3/4 and add a high gravity yeast, then start sugar additions a day or two later.
Also, I personally believe that higher mash temps make better final products. It will seem counter-intuitive as your FG will calculate higher, but remember that you will be adding sugars along the way that will thin it out. Low mash temp + sugars makes for a final product that can be super thin and appear of lesser quality than commercial products. Even a mash temp of 153 isn't that high but can help.