Hi John,
Okay first up you must definately not call me "Sutton" again,or I'll start to refer to you as "Ganter" LOL 
Seriously though my friend in reference to your Q's here goes.........
As for the overall weight i'll need to do a check first,although will say this though, they are considerably more lightweight compared to my previous melamine/chipboard racks.
The approx.dimensions of the rack pictured are Height 134cm Width 98cm Depth 58cm.
I estimate you could perhaps go a few more levels higher,but I recommend that users should add stability bars.This aspect is something i'm working on at the moment with a ball/boa keeper pal whom the rack was built for.
John as you can imagine when creating something from scratch only time and testing will allow the possible improvements to become apparant.
I made quite a significant advance in the whole shelving set ups from the first two I made for personal use and testing a few months back.
FAR too long and detailed to type up/list to be honest,plus I'd be rather foolish to just give away all the knowledge,sure you'd agree.
Right now i'm totally settled on the design and can't see any changes I'd need to make.I'm currently thinkin hard about a plastic viv design using similar materials as the racks.
John, fire me over an email and we can talk more on this if you wish
Ginter hatch pick!! Now theres a SWEET offer not to be sniffed at. LOL
cheers........AL