Ok if normal 20mm models are in base contact you can the guys either side of your modal can attack Now what happens where you have a unit of 25 mm models vs a unit of 20 mm models can you still attack diagnally. eg sw =saurus warriors z= zombies SWSWswswsw zzzzzz its hard to do with letters but the one in the middle in caps is in contact with the zombies but the other is not touching them. Can he still attack as he is next to one that is.? can he attack diagnally?
Corner to corner contact is the best you can do for attacks, it must be at least that. You cannot just use the model next to if there is no corner to corner contact. In your example you have 5 saurus warriors across (125mm) vs 6 zombies across (120mm). If you maximize contact between them, they will all easily be touching.