Wow, what can I say except that I'm truly humbled. Thanks!
What you are showing for your gantry is pretty much identical to my plans to upgrade my gantry to R&P later in the spring. Be sure to make a solid connection to the gantry uprights because a wide gantry can easily twist at these connection points.
When I transfer the whole mess over to a steel frame my plans are to raise the rails higher above the bed and shorten the gantry uprights correspondingly for two reasons. One is to stiffen the upright supports by making them shorter, the other is to place the rails about 4" higher above the cutter tip for most 2D cutting jobs.