Head Gasket Help

Hopefully someone can help me with this. I have a '97 Fiat Punto. A
couple of weeks back the end of one of the spark plugs dropped off into
the cylinder.

I removed the head, cleaned it all up, got rid of the bits of plug,
checked for damage and refitted the head with a new gasket.

A compression test showed that there was not very much compression in a
couple of the cylinders and further testing showed that the compression
in all cylinders was all over the place. I removed the head again and
oil had made its way from the oil galleys and seeped out into the
cylinder. I assume thats where the air was leaking out too - through the
head gasket.

So I got another gasket, a proper angle gauge (I guessed the angles
before when I tightened the head bolts) I cleaned everything up a little
more than before, oiled the head nuts more, and reassembled. Compression
was even worse this time. If I try to start the car it turns over but
misfires through the throttle body (sign of a blown head gasket?) I
assume that the gasket has blown/not sealed properly.

Can anyone give me an idea of what might be causing the gasket to not
seal properly.

Only things I can think of a

I've not cleaned the mating surfaces properly
I've not tightened to the correct torque for some reason
The head is not perfectly straight.


Are there ANY other factors at all that could cause a newly fitted head
to not seal properly?

I assume that if I can see where the oil has made its way through the
gasket that means that the gasket isn't sealed correctly? Theres nothing
else that would cause oil to make its way into the cylinder?

I'm at my wits end with this damn thing.

Cheers,
Dave