I am certain there is some archaeological evidence. A lot of people got smoked via crucifixion. The truth is I seriously doubt there was a standard – they used what they had at hand.
Given that the crucifixes got covered in blood, urine, feces and other bodily fluids through their use, I too seriously doubt they were fancy hewn crosses.
I submit that the Romans were pretty methodical about things. Very good at designs and building,. Their army, who more than likely conducted these affairs was also very methodical in fact almost maniacal in its precision. The way they dressed, the way they fought, the formations they used to both fight and march their entire military bearing was an awesome spectacle.
Yet, in this area, state executions of convicted criminals and other undesirables, you would have us believe that they rummaged around in a dungheap, grabbed whatever wood they could and slapped together something haphazard. That really doesn’t sound like something they would do at all and is totally contrary to any historical evidence yet found…
I would think that the upright posts which stayed in the ground normally, were very sturdily built and would have had to have been so. How could they not have been? The cross beams, carried by the convicted to the place of execution likewise had to be sturdy enough to support the weight of the condemned despite any struggling and convulsions the condemned would have made in trying to escape such a fate. Do you think you would just hang there and not move??
I don’t think so.
I have never thought there was a precise size or shape, but I will guarantee if these things were made by the Roman Army , they were pretty well made. And, if they were made by a cottage industry in the occupied territories, I doubt the army would have bought junk, so the crosses would have probably had to meet certain minimum standards,
As I said the Roman Army was not known as being an organization that tolerated much deviation in any area at all, and I would have to think that they would not treat public executions, which were meant to both terrify and intimidate the locals, as being anything less deserving of their attention to detail