I would put the SS Controller in the first pole, then try it at various spacings and see what works best. Try you ideal length your wanting. If it doesn't work, you will need to shorten it up.
Is seems like 1 module is not much per pole at all. You might want 2-4 per, but thats more cost. If you figure that a a smart string does 128 nodes for almost 40' ... it just depends how much voltage and signal loss occurs between modules and how important inline modules are for the re-transmit of the data along the way.
I think if you only had 3 poles and embed the SS controller in the first one, your really only going 24' total, which seems reasonable unless the data signal gets lost on a 12' run. I'm doing something similar but with shorter wire lengths between modules and more like 3-4 modules per display item.
You could use those SS coop 3 core quick connectors to try different lengths and make setup easier for each pole.