Everyone's tastes are different, so experiment to find the ratio that you like.
I found it was easier to experiment using factory bread, before switching to homemade bread.
Sprouts (5 days old lentils) on top of sun dried Tomatoes, on factory made bread:
after adding mayo then Bacon bits:
complete sandwich in a frypan, with more mayo on the top slice of bread, to help hold contents in place:
different angle:
closeup:
after grilling and cutting diagonally:
some of the contents may spill out during grilling/frying, which isn't a problem if you use the frypan as your plate :)
half of final sandwich, showing contents: