Extract (highlights are mine)
"Stauros" interpreted as a cross in the case of Jesus[edit] The New International Dictionary of New Testament Theology, dealing specifically with the crucifixion of Jesus, says it is most likely that the stauros had a transverse in the form of a crossbeam. "Secular sources do not permit any conclusion to be drawn as to the precise form of the cross, as to whether it was the crux immissa (†) orcrux commissa (T). As it was not very common to affix a titlos (superscription, loanword from the Lat. titulus), it does not necessarily follow that the cross had the form of a crux immissa."
"most likely" implies a preference not certainty!
IMO, in the absence of much evidence either way the debate as to whether Jesus was crucified on a cross or a stake is nitpicking. Either way the death was prolonged and painful.
Some Christians use the cross as a symbol of the event - there are more important things to worry about.
