The cross sectional area of the "nails" used might have some bearing (bearing get it? ) on the outcome.
A large square section nail with about 13mm or above shaft width near the head would be capable i would have thought of holding a man up by both hands / wrists. If the head is quite a bit larger than the shaft (say 40mm+) then it will act as a clamp when hammered home enabling even more weight to be suspended.
i dont care either way, cross or stake, if he existed at all he was just another deluded fool.