Morgan's Master blend crystal malt extract

[Wyvern]

Hi, I am new to this forum and have been brewing for about 4 months,

My question is simple, has anyone used these extracts before?

I am making an 18L Brew of trappist ale and was thinking of the following recipe but i'm not sure of how much of the extract to add.

1.5kg Light Liquid extract
1.5kg Liquid Amber extract
***500g Morgan's Master blend crystal malt extract***
500g dry dark extract
500g Dark candy sugar
40 g. Hallertau Hersbruck boiled 60 min.
17 g. Hallertau Hersbruck boiled 15 min.
17 g. Saaz boiled 2 min.
White Labs WLP530 Abbey Ale yeast

If anyone could point me in the right direction that would be great.