Here you have some engine pictures.
Engine general view
Engine close view
Not bad for a 1988 car!
Weber 34 DMTR detail
It works fine except for the aircon (seems to need regassing) and idle, which is unstable. But, all in all, it is a great car!
I have finally put back coolant hoses and filled circuit. In my car, I have not been able to locate any purge hole except the one in the radiator top. So I have filled through the expansion tank and, once coolant has reached the purge point in the radiator, I have closed it and have continued adding coolant until it has reached the max level. Once there, I have started engine, carefully looking for any leak and of course for coolant level. When temperature has reached about 85C, thermostat (which is marked as 86C) has opened and water has gone through radiator circuit. I have waited a bit more and then have checked that fans work as they should. Then engine has been off for some time and have rechecked coolant level, adding about 100cc more.
So, all in all, it seems repair has been successful :-) and gasket substitute has worked fine so far. I will keep an eye on leaks and coolant level for some days and will top if necessary.
Thermostat housing removed
Thermostat housing replaced
I have also worked on the unstable idle. I have adjusted idle rpm and have got a pretty good idle at about 850-900rpm, a bit on the high side but lots better than the 400-800 rpm oscillating idle it had before.