I just did a cheap trick with mine after mounting 2 6x9"s, 2 4"s and a shovel and axe on the outside...
Get an extra strut...
Take two little pieces of 3/16" plate and drill two holes (same size as the male threaded stubs of the strut) in each about 1.5" apart - next un-thread the ends of the struts off and assembly a pair together - I could then run three struts on the hatch...
Matt