They generate a lot of "recycled" body heat, so start him out at a hour and build up the time gradually.
I use the Quick Wraps and Hock Wraps on two different horses; I won't leave them on all night in case they would get hung up on something.
Four hours in the morning works miracles, if that is possible.
With the Quick Wraps, I velcro the middle strap first and try to judge "one finger tight".
It's almost impossible to get the bottom strap too tight, so I pull it around enough that there is a bit of "wiggle room" when I hold the ankle area of the boot and jiggle it.
I do the top wrap last, making it 1 - 2 two fingers tight.
Again, I only need to leave them on four hours day.
If you're planning on leaving them on for 8 hours in the stall, I honestly would call Back On Track and ask them how much to tighten them up. Their customer service gals are terrific