I have an Xantex ST1500 which has several DC input connections. I recently went from 4 panels to 8. My question is: Is there an advantage to running separate wires from each group of 4 panels to the inverter over having a combiner box out on the pole? One group of panels gets shaded a few minutes before the other 4. Is this detracting the power the other 4 are trying to send to the inverter in the case of a combiner box or does the inverter not see it any differently than if each set had it's own run of wire to the inverter?
I hope I've explained this properly.
thanks in advance

It makes no difference if the panels are combined at the pole or the inverter, its electrically the same. What can be a benefit is when running the strings separate, you can use larger wire for each run makings the losses lower than a single monster run.

For example, you should be using 6awg for each string of 4 panels ( a guess as I don't know the panels, amps, distance ) so thats 4 6awg wires for the two strings ( two positives , two negatives ) ... to keeps the same losses with a single run, you would need 3awg pair ...