Aaahhh... pictures are 1000 words etc!
I'll check out the vids again, how does that design cope with lateral loads (gantry side to gantry side)?
Would you consider Stainless steel with that fully extended?
My gut feel is that you wouldn't?
I did read your 1st build and was very impressed (I'm sure I have watched the video). I'm sure I'll read it again (along with many others).