IFN far red tandem conjugates & a question for Mario

Cytokindred,

After some initial negative experiences long ago, we have generally limited
ourselves to using non-tandem conjugates for our anti-cytokine mAbs used for
ICCS. I'd like to revisit the issue and try some anti-human IFN-g tandem
conjugates, particularly those emitting in the far red, such as PE-Cy7 and
APC-Cy7.

I am requesting feedback from individual investigators regarding particular
products they have used successfully. All replies I get will be considered
for non-confidential unless you specify otherwise.

Company reps are welcome to email me directly to inform me of their
product's availability, but please do not reply to the list.  

Mario: A question I have always wanted to ask you. My instinct is to refer
to a tandem with the excited dye noted first and the emitting dye noted
second (e.g. PE/Cy5). I use this order because it is in the order in which
the light energy interacts with the tandem (first excited, then emitted).
Mario, you always use the opposite convention (e.g. Cy5/PE) and must have a
good reason for doing so, what it it?