Im not sure about bench bleeding, it's so hard to keep air out while you get it back in the truck. Any master cylinder will expell residual air out the fluid inlet hole on the first small part of the stroke. As above, set the truck so the master cyl is level or so the fluid inlet hole from the reservoir is slightly high.
I cannot think of any reason why a manual trans makes any difference.
Try bleeding with vacuum. With out vacuum, make sure you have a solid pedal and working unboosted brakes. Check that remote valves, proportioning valves, etc, are mounted the rightway up so as not to trap air.
it takes some heat to boil fluid but its possible. Any brake line should be at least a foot away from an exhaust. You could rig a temporary shield from tin cans and duct tape on the lines, not the exhaust, to test that one.
good luck.
