How many yards of fleece fabric would I need to a very tall guy?

I like the solid part of these blankets to be at least as long as the person is tall - that's long enough to stretch from shoulder to toes with enough extra to wrap around and tuck under his feet - so I would get at least 2.5 yards of each fabric. You'll use about 1/4 yd of the length in the ties, leaving about 2.25 yards for the blanket, which equals 6'3", which is the length you want.