Do type II and III actually produce less local unit types then type IV

[Harpoon]

.. types than IV? Or does it just depends on the area of the map you're im? Because I don't want to be forced to use zero command local leader to defend a garrison far away...

[Dargaron]

.. types than IV? Or does it just depends on the area of the map you're im? Because I don't want to be forced to use zero command local leader to defend a garrison far away...

The main difference between the different Gov types in EB is in what buildings are available. For non-nomadic factions (besides Carthage, IIRC), the system works like this:

Level I Government: Unlocks level 5 Factional Barracks, Level 2 Regional Barracks.
Level II Government: Unlocks level 4 Factional Barracks, Level 3 Regional Barracks.
Level III Government: Unlocks level 3 Factional Barracks, Level 4 Regional Barracks.
Level IV Government: Unlocks level 2 Factional Barracks, Level 5 Regional Barracks.

Carthage is special in that Carthaginian Gov buildings unlock Regional Barracks one level higher than normal e.g. Level I would unlock Factional 5, Regional 3.

So, depending on the type of units available in the region, it may be worth it to build a level IV government. For example, in Gaul a non-Celtic faction needs a level IV government to recruit Celtic Heavy Cavalry (Brihentin). But in general, most regional units only require a level III government building to recruit.

[Harpoon]

Ok so for example
http://img521.imageshack.us/img521/7836/gaulsdt8.jpg
In sergesta and the city to the right of it (can't really read) I can get away with a type III because it's light grey on the map so I can't build the best units there anyway (I want the heavy cav) , but with mediolanum which is white on the map (all units available) i should make a type IV to make sure I take advantage of the extra units like the heavy cav?

[Dargaron]

Yup, that's pretty much it. If you want to recruit the heavy cavalry in those cities, you'll have to build a level IV Government Building. That doesn't mean you necessarily want to build a level IV in every province where you can recruit Brihentin, since it does restrict your economic buildings.

Also, if you want to eventually upgrade the government type in the city, you will still be able to recruit the heavy cavalry. You just need the level IV to build the highest level Regional Barracks. Once the barracks is built, you could destroy the level IV and replace it with whatever other kind you want. Some people consider this an exploit, though.

[Harpoon]

Ok thx