Water splitted from the overflow coolant

[alcubot]

Boys after the substitution of the old cap (rev. 00) with the new one (Coolant cap - 996-106-447-04), and after have setted the level of the water at 3\4 of the max, the problem seem to be disappeared, no more water splitted.

After i've done some tests to verify the integrity of head gaskets of the engine.
1- when the temperature was at about 80 Celsius degrees i've unscrew the water cap to see if the water, when accelerating, was going up (bad signal) or down (good). In my case it was going down.:-)
2 - after i've drived the car in the higway and inside the city continuously and the indicator of the water temperature is arrived in the middle between 80 Celsius degrees and 100 Celsius degrees, so i think about 90 Celsius degrees. External temperature was about 15 Celsius degrees. 90 It's a good operating temperature?

Have you some other test to verify the the integrity of head gaskets of the engine?
Excuse me for my bad english...
Thank you in advance
A.