Good morning agil,
Is 1.8m the maximum size that you can install in your house/apartment?
If you can consider the next size of 2.4m, then you might pick up some more channels from both satellites.
My two dishes are aliminum and I am happy with my choice.
Can't comment about fiberglass.
You might be interested in this thread:
Astra 19.2E Dish Size in Israel
Not many replies from fellow country men, but would like it if you or your friends can add some more replies there. Thanks.