Multivalent Ligands vs Monomers

I'm characterizing the interaction of a viral glycoprotein with a host protein and I got a question from my thesis committee that I dismissed initially but now I'm wondering if she might be on to something.

I've been immobilizing a biotinylated Fc fusion on a streptavidin chip and assuming that the divalency of the Fc fusion is irrelevant/negated on the surface of the chip. Is this a reasonable assumption or is this something I need to factor in to my analysis? I can honestly see it both ways:

Case 1 - The divalency of the Fc is negated because of the large number of binding sites on the surface.

Case 2 - The two binding sites of the dimer are closer together than the distance between nearest neighbor molecules on the chip so this could artificially extend dissociation if/when the analyte fell off and immediately rebound to the other binding site on the same Fc dimer.

Any thoughts on which of these interpretations is the correct one? I can honestly see it both ways. I have an experiment planned to answer the question (amine couple both Fc dimer and monomeric extracellular domain) but I'd be curious to hear what other people think.

SPR theory states that when a multivalent ligand is immobilized every binding site is treated as independent. As with the amine coupling which results in a random immobilization and therefore different degrees of accessibility, when binding sites of a multivalent ligand are close together, they can have different accessibility depending on the size of the binding analyte.

Case 1 – I think this is correct.
Case 2 – is similar to a high-density sensor surface (mass transport). If you raise the dissociation flow rate and the dissociation stays the same, there is no rebinding.

I am really interested in the outcome of your experiment.

Kind regards
Arnoud