Cyldinder Head Stands

I'd like to build a set of head stands. I've got plenty of metal laying around and I don't feel like paying even for the cheap ones on Amazon, they are too simple. But I'm a little curious about the tapered area on the shafts. Does the head land somewhere on that taper, or is the spike suppose to go all the way through? All the pics I found show it up on the taper so I'm guessing the rod is 1/2-5/8" diameter? Need to know so I can size the rod appropriately. If anyone has dimensions that would be great. Is there a better style than the one in the link? Don't want to put too much effort into this though. I'm mainly going to be assembling/disassembling the valve train and I want to CC the chambers. Maybe a bit of polishing but I don't want to go to a fully Monty, adjustable setup just yet.

https://www.amazon.com/dp/B000RUBAFW/?tag=joeychgo-20