I think it would jar if you were to combine the two together to make one.
Using our various region maps as an example. When combined together as Redrobes did, they jar if you view them as a whole. If, however, you look at a master index as you yourself first made for the LandGrab, and I say: "hmm, I want to look at region 6 (my region), then I am viewing all of Region 6 at once, separate from the other regions. If I then decide to look at region 7 (redRobes' Thrubmorton Fens area), it doesn;t matter if the map style is different as I am viewing it different from Area 6. BUT, put the two together side by side and view them at once and now suddenly it is difficult.
Hence, if I were to map out for inclussion into your map of the town of Kwourin using my distinct city mapiing style it would not mesh, and would need to be redone to have it look right.
See the example ofr Kwourin with a section from Deestan superimposed. Looks weird, and you would need to rework it for it to 'fit in' and seem to be a part of the whole.