Man, I wish I had your fluency with 3D CAD Pete! I can do it but it takes me way too long. Let me guess; you use it in your day job?
I like your 1st suggestion with the plate across the front better. I have enough 3/8" flat plate to do that but planned the other method to save some of it for other projects. Someone else suggested that as the bridge gains lots of weight, it increases the chance of a tip-over at the extremes of table travel. Ouch!
I presume that your suggestion with the pucks requires the pucks to be a snug fit inside the crossbraces and needs bolts going through them into the pucks on the sides as well?
I hope I don't need to add diagonal braces to the table as well Roger. I don't want to muck up that pretty blue paint. You may well be right but my SWAG engineering says I won't have to.