Can you show us the map? You can upload it to the problems section. That'll give us a chance to look at it and give more detailed explanations.
Just a question about those wires bytheway, are they func_walls or normal brushes? You'd better make them func_walls or even better, func_illusionaries in this case, since these don't block the player. Entities in general are easier to handle for the vis process since they don't cause extra face and node splitting. As a rough thumbrule, make every small, detailed brush a func_wall, or if it's better that it doesn't block the player (small wires and stuff for example), then make them func_illusionary.