Thanks to all of you....
Some sentences to the behavior of the card...
CB= -135°C
1920 possible from -115 to -135
1947 needs -125 to -135
1960 -130 to -136
1970 -132 to -137
Dunno why, but CB goes up a bit with clock..not with voltage!
Catzilla sometimes need a lot ln2, sometimes even not...the biggest problem is keeping the temp...