Need army advice - Koreans, EA, Level 121

[Persia]

I have been using the same army composition for months with very little change; as I've gotten slightly more troop space, I now use 40 Heavy Singijeon, 3 Supply Trains, and 6 Cannons. However, I have an army completely upgraded, apart from ten more troop space from Standing Army (which is going to be prioritised), so it's important for me to start incorporating regularly troops like the cuirassier or guard mortar; I've got a Heavy Gatling Gun and Guerrilla in my factory which I have not touched for weeks now. Has anyone been in my situation or something similar? I currently have 115 troop space, and have done the research which reduces troop space for certain units by 1.

 

[detymi]

I play as Brits (currently lvl 102, also EA)
I have researched the whole Standing army and I use this composition:
3 HC, 2 Supply trains,6 cannons and the rest shooters
When looting, the HC helps me saving shooters and cannons from mortars and towers
In WW, I add extra shooters instead of HC as I request tank from alliance and also have Cavarly or mahout as mercs