I will tell you that I saw a frame rail flange get bent by the crossmember/skidplate mount being on just the flange. There isn't really enough strength in the flange for it alone to support a decent impact on a rock. If the vertical portion shares the load, it should be much better. This is my idea from being around semi trucks for years. The flanges on those frames never do all of the work if supporting the weight, it is shared with the vertical steel.
Just something to consider if you are planning for upgrades, at least in my opinion.
Nice parts and progress by the way!