Jigsaws are dangerous things aren't they ?
You can cut a lot away real quickly.
How about bonding some alum extrusion (10 x10 Angle eg ) to the outside of the 'truss' struts. Epoxy or even silastic would stiffen it up immensely although it might defeat the whole weightloss idea. You'd have to figure out the loss/gain but you could also reduce the truss widths further.
In fact, taking it to the ridiculous. Use 25mm square or round maybe and create the trusses and secure them to top and bottom etc. Then cut away ALL the middle section. Hey Presto, instant truss scope !! All aligned as well.
Sorry, got carried away there for a moment.
