Dear Jacob, agree, it's a mess. From what I read, the glutataldehyde concentration should be low (<0.01%) and the x-linked complex that you get should not occur in high salt conditions (reasoning that 1.2M KCl would break the average complex apart). Have seen papers where more selective zero length crosslinkers have been used - the Pierce catalog used to have lots of them - it seems it boils down to the same problem, eventually you will find one that "works" but you will need independent evidence to convince yourself.
I typically make really nice MW size ladders with my monomeric negative control proteins, though. Best, Herwig * * * * * * * * * * * * * * Herwig Schüler, PhD PI, Structural Biochemistry Structural Genomics Consortium, MBB Karolinska Institutet Scheeles väg 2 S-17177 Stockholm