Madoushi a warm welcome to you.

I would build type 1's and 2's wherever possible. If neither are possible, I would sooner go with a 3 than a 4. With 3 you reap benefits of some factional as well as a lot of local troops. Type 4 is usually unnecessary most of the time, and the allied generals demand a hefty salary. Keep a levy garrison in your type 3's and you'll be fine.

I'm curious, as a Camilian era general, what are your armies currently consisting of? (i.e. how many of each unit type do you have in your current, standing armies?)