Some of those timbers are somewhat oily in nature and would benefit from a good wash with an acetone soaked cloth to ensure the glue stays stuck. Also remember to only use enough clamping pressure to bring the timbers together, you don't want to squeeze all the glue out and have a dry joint.
I would glue them one at a time, that is, glue the first two and wait for the glue to go off before gluing the third piece and so on.
For what its worth, Spotted Gum is no longer referred to as Eucalyptus Maculata, rather, now it is Corymbia Maculata.
Boatin:-
Spotted Gum, the heartwood is pale to dark brown, Sapwood to 50mm is distinctively paler but there may be a zone of intermediate wood which may be a complicating factor. To put it simply I guess ..... it's brown ..... you choose which shade of brown.