You only consider the halves adjacent to the summer tile.
In this regard, I received some other clarifications I haven't posted yet affecting Watchtowers and Exp. 8 castles... I need to complete these clarifications with a few more questions, but it seems seems that when looking for features (roads, cities, watchtowers, water...) on double-sized tiles (and therefore on wonder tiles or 2x2 tiles) only the
adjacent square spaces are considered.
It sounds reasonable to me (the grid rules), but I need to see what happens when looking for meeples (e.g. watchtowers).
