[Marcello]

"Cloche (the two on the ends are GFM, the center one is for an automatic mortar that was never perfected)"

Do you mean the 50mm mortar? AFAIK it was a standard feature across the line.

Besides the above bloc and the GFM cloche a few others standard types would be needed

1) The main entrance bloc (that with the narrow gauge railway)
2) the standard mg turret;
3) the standard twin 75mm turret;
4) the standard twin 82mm turret;
5) the standard twin 135mm turret;
6) An infantry bloc armed with mg;

With the ones above you could build most of the typical forts of the line. Now if you want say a 100% exact copy of Hackenberg you will have to crank out 25 icons, many of which will be non standard, but for a typical fortress the ones above will do.