Big and Tall with leakage

Hi. I am a giant. I'm 6'11" tall and over 400 lbs. I use Depend and sometimes store brand Guards for my leakage. My main problem is urgency, when I have to go I have to go! Unfortunately, the Guards are a bit small around certain things and I tend to have leakage around the sides. Also, I love to wear boxers most times. I really need a big and tall sized protector, and possibly something for boxers. The ones I use help some, but I want it to fully protect me from embarrassing accidents.