So, for the lore reasons, in this image, the footrests are cut from ancient trees, as the once great forest of Lothlorien has provided ample lumber for this execution.
As for the "reality" of the cross: It's softwood that was sun dried for several days, mostly 3x6 pieces, by with no structural pieces less than two inches in thickness. It's based off of a CAD setup that I made myself, with no nails required for the joiners, to produce the best results. The CAD file was taken into blender and roughed up a little, and given a procedural texure that allows me to not use the same cross shape twice; even with the same design, the crosses have different nail holes, wood chipping, and grain texture. Where the end grain is showing on the pieces I took care not to include the pith, and cut just slightly off-center, to get the most out of the thicker, denser grain at the center of the wood. The boards that make of the top of the footrest and the titilus can crack with no consequence to the structure of the cross. The majority of the wood of the footrest is contained within the support below the plank that their feet are nailed to; the plank serves primarily as a crude washer of sorts between the feet and the rest of the wood. Since the footrest is joined without nails, the stipes is much more durable to repeated crucifixions.
Given the nail thickness and the expected load, I'm within tolerances.