Great looking grill and spread! Griddle photo is impressive.
re: Mac recipe/link Not sure I would be adding the sherry either or what it contributes or possibly covers up. Just speculating, it might add a little bite that may be lacking in the gouda/gruyere. My little place used Colemans dry mustard and found it could also provide bite/sharpness that cheeses may lack.
Your extended family is very blessed.