Someone in the Netherlands has tried 5% of the 1900 EBC to brew a dubbel, and his experience was: too much burned raisins and too full to be like the Westmalle Dubbel, but nice nevertheless.
To get to 33 EBC and 1.055 OG the following candi syrup combinations of the 1900 EBC and 180 EBC are possible for me:
[EDIT] confused SRM and EBC. Stupid SRM!
0% 1900 and 15% 180 EBC
0.4% 1900 and 11% 180 EBC
1% 1900 and 5.5% 180 EBC
1.4% 1900 and 0% 180 EBC
0% 1900 and 7.7% 355 EBC
0.4% 1900 and 5.2% 355 EBC
1% 1900 and 3% 355 EBC
1.4% 1900 and 0% 355 EBC
[/EDIT]
Since Brother Antoine wants 2 of everything I'll go for either the second or the third combination.