Hi Jeff, i am just getting a guy to steel strap my tank in, hope you dont mind me showing him these pics,.... more to the point .. i hope he does not mind me interfering 
just one little question for the ever cautious me!! 
are those little square plates underneath , strong enough to secure a 650 upright, with the force and pressure they will excerte whilst cornering and breaking....
knowing how precise and safety concious you are.... it maybe a daft question...
but i thought i would ask, for my peace of mind Jeff.
Thanks.
Gary.
Hi Gary
No safety question is daft in my mind.
The plate underneath is large enough for your tank you can make them larger if you wish, there is no need for them to be to big unless you have a couple of bolts within a short space of each other then the plate needs to be long enough for both bolts.
You may be supprised just how stong chassis are on vehicles but the plate helps to spread the load on the chassis.
One point I must make to you, is you will need to add larger nuts/bolts for your tank, than the ones I used the bolts take a lot of pressure.
I don't mind you showing your guy, I just hope he's understanding lol
what type of steel for plates was used and also size cut
I used Mild steel, I measured them to fit my daughters van, Just pop underneath your van with a tape measure and measure the width of your chassis, its not a problem if the plate is a little wider than your chassis.
My own plate was 6mm x 60mm x 150mm and thats fine for my own tank