Think my HG has failed and need to replace it again. So what you think the best time will be. Not bothering to skim the head again, so thinking on just loosening the exhaust manifold and then replace the gasket.

I think I could do it in a few hours. All going as planned anyway. It's not a big job really.

Compression measured with all spark plugs out is:
1 - 225psi
2 - 190psi
3 - 216psi
4 - 225psi
So compression is reasonable, but 2 is lower then the others. It also seem that gases escape into the coolant when the engine is under load. So the compression are not a definite answer at the moment.
So what you think shall I do? just replace that gasket anyway?

I'd replace it, You will have to skim or replace it only if the heads warped or damaged, you will have to check this once the head is off the engine block.

You can do the HG in a few hours if you Know what your doing and have all your tools and new parts out. I found that draining, flushing, replacing and bleeding the coolant took the most time. 6 hours should be enough to do the job Unless the head is damaged of course.

Finished the job today. And yes I think altogether it took me about 6 hours. 3 hours to remove the head yesterday evening and about 3 hours to put the new head gasket in. Decided to get a non eBay headset and have to admit that the parts in the kit are a bit better, hope they also last a bit longer.

The car seems to be driving a bit better and quieter, too. Also it does not seem to have a small misfire at idle which I had prior the change of the gasket.