In general I conquer very slowly and thoroughly, and avoid client rulers when possible as they are often really horrible administrators, but decent generals. But when you do not have the family members to spare and the city is quite far off, then a client ruler is a must.

I usually colonize far from my homeland, usually the Peloponnese as KH, so my system is;

ENSLAVE, sorry. We are 'civilized' but not stupid, we do not want to expel too many people, but still don't want a large and resentful populace.
Type IV after Martial Law, to institute a client ruler.
Sanitation or roads to set up basic infrastructure
destroy type IV and institute the 'best' type of government possible, usually a III since my colonies are often so far away. I do not mind keeping local traditions when its useful, but a degree of Hellenic style government should be in place.

I then usually, by bits, destroy and replace non Hellenic structures with the Hellenic equivalent. I take great joy in 2 things in EB and it might be a disease; Building paved roads and Hellenizing distant lands like Arabia, Euxinus and England.

I also role play by degrees by having at least one citizen militia in each colony, as a way to create civil solidarity in my new city. I do terms of 2 years, disband, then retrain them or promote them to a semi-pro soldier. So Militia to Light Hoplite