I have just changed the coolant on my 99 S2, used Honda coolant as well. I have bled all the air out of the system and the car runs fine and I get 3 bars on the gauge.
My problem (if there is one) is that when I start from cold it warms up perfectly to 3 bars the top hose is hot and the top of the rad is hot, but it takes ages for the bottom of the rad/bottom rad hose to get hot, the car doesn't over heat and the heater blows hot. I have taken the car on a 100 mile drive and it was perfect
What I'd like to know is how long does it take for your bottom rad hose to get hot from a cold start ?

 

The bottom hose stays cold if the thermostat is closed, and the thermostat stays closed until the engine reaches a certain temperature. There's simply no need for the thermostat to circulate coolant flow through the lower radiator hose if the engine temp is still below the threshold

 

Just a highly efficient rad. by the sound of things.

It's meant to do that.