It is debatable whether hermetic politics should follow mundane politics or not. On the one hand, why shouldn't it? On the other hand, because it's part of the Oath to avoid mundane involvement and Quaesitores police it. So, an attempt to redraw a tribunal border because the mundane land has changed hands would be seen as suspect by the Order.
There is a case to be made for following closely cultural/linguistic divisions but on the other hand the Order of Hermes, like the Church, works in Latin.
Now, specifically about the Tribunal of Iberia, I would question the clear-cut separation following the progress of the Reconquista, not least because the concept of the Reconquista is a later historiographical conceit. Until at least the 11th Century there is no real sense of it. The (in)famous El Cid was a Christian mercenary in the service of the Moorish king of Zaragoza. There is a battle of Barbastro in 1064 and then Las Navas de Tolosa in 1212 which partake of the Crusader spirit, but the Tribunal of the Levant is not divided politically following the progress of the Crusades either. This is unless you want to say that Al Andalus is dominated by the Order of Suleiman and not the order of Hermes.
On this point I would also suggest waiting to see how the new Tribunal of Iberia book written by @amseriad and @Galdric does Iberia. They have reworked extensively both the mythic and the hermetic histories.
To me, the idea of making a Catalan tribunal an off-shoot of the Lotharingian tribunal which is being pushed south by the Norman one is amusing. But I have two objections. First, the historical Catalan empire was Mediterranean-looking: at one point it included Sardinia, Sicily, Naples and parts of Greece. Probably the Ebro river and the mountains to the South of it ensured that the Reconquista was mostly a Castilian affair. Second, Hispania was at least as integrated in the Roman Empire as Gaul was so there is no reason hermetic influence needs to be carried into Iberia from Provence by the Flambeau. It could just as easily be homegrown. Iberia produced Popes and Roman Emperors, and the Visigoths that overran it were thoroughly romanised unlike, say, the Franks. So Iberia could well be similar in flavour to Rome or Thebes in terms of old Hermetic tradition. Also, Al Andalus was a cultural powerhouse in the high middle ages, so it would radiate magical influence into Europe and not the other way around.