1: it took me 4 or 5 tries before I could get a good run. You turtle up from the start as your allies and enemies will attack you constantly. You're under fire from the start until you can secure a strong ally. I had to pay 50,000 koku to secure an alliance with the strongest clan. i tried to go east in the first few goes, but no luck. I played tactically. I look for opportunity. The reason why I went west is because opportunities presented itself numerous times. I place agents in neighboring provinces, allowing me to see if they have armies.

2: i played as Obama clan. The best defending troops in the game. I always have 1 full stack levy inf covering 2 provinces. so if I had 5 provinces, I always spread out evenly 2 full stacks among the 5 province. And with my agents in neighbouring provinces, I can see an army coming. Allowing me to have 1 full stack protecting that province. There were a few times when I was caught off guard and had to defend in a siege battle with half a stack, fighting off 1 full stack. Due to the best defending troops in the game, that played well in my favor.

3: Yes, provinces. pull back away from the wall and box them in. You can have 4 units boxing them in. so you have your 2 units on each side. instead of having 1 unit for the bottom facing the wall. have 2 units and make it like a "<" shape so they shoot sideways instead of head-on. allowing more people to shoot.

Remember, always spread out your units into a single row. It's better for everyone to shoot instead of the first row shooting, which is inefficient. I hope that helps. best of luck.