Need some Shogun 2 help

I'm playing with DMS in the Sengoku era.

• Which troop bonuses should I go for with a Blacksmith and Encampment?

• Right now I'm going for double armor but I'm not sure if thats best

• How do I reduce my unit upkeep costs?

• When I look at the AI troops, their unit's upkeep cost 66% of mine. So, they get to field huge samurai armies while I'm stuck with ashigaru.

• I know I can reduce upkeep with arts, generals, agents, and commissions, but it isn't enough. The moment I recruit a samurai army my income dips to nothing.

• Also, doesn't DMS remove AI bonuses? Why does the AI still get cheaper units?

• How do I fight more land battles?

• Literally all my battles have been siege even the automated ones. It's getting boring to rinse and repeat the same exact process.

• I want to fight more other battles...

• Best army composition?

• I'm leaning towards spears because that is historically accurate. Samurai weren't katana wielding footmen that charged at the enemy.