So here I am back again for the latest update. There have been so much to do, so I had to leave this for some time, sorry for the delay. But anyway, things have been solved!
I searched for a while for solutions before I found a webshop names techbay in Norway. They gave me some advice and to two shims made of copper. They are 0,5mm thick and sized like the top of the gpus.
And when applying thermal compound, it's recommended to do a double cross with a fat middle.
So I've applied compound on the gpu, put the shims on top. Apllied compound on them too. Then mounted the waterblock.
Now I got an idle temperarture of 31°C, and heavy load of 52°C. As the cooling liquid will after a while be warmer the max temp might rise as well.
Cooling liquid temperature is between 22°C and 31°C, depended on the room temperature. Soon winter in Norway so I don't think temp will be a problem
Luckily the gpus haven't been fried. Since there was a gap between gpu and waterblock, and with just a little rice size thermal compound there was almost no thermal transferring.
Next to be done is motherboard fan control. Need to bring down the rpms on chassis-fans. Too much noise