Finally got the rear shop cleared enough to cut up the aluminum sheets. 1/8" 4X8 sheet is a bear for one guy to handle.
After rigging up some support I was able to cut the sheet in half, and that size can be handled with good control.
After giving up trying to cut the stuff with the jump shear, I found that an 80 tooth carbide blade cuts the sheet easily, so I was good to go.
I cut off the rear protrusions (HV terminal insulators) and the top mounting bosses, as I will be mounting and wiring it differently than it was on a stock pack.
Got my big brake set up so I can make nice bends, so I think I will make the pack so it screws together rather than welding it together. This will allow better access in the event of a problem.
Still need to make the air inlet and outlet sides and then locate and drill the main mounting holes for the pack core into the case, as well as the 4 main mounting bosses