Comments of chapter undefined of Walker Of The Worlds

LM keeps building this incredible foundation like he's going to build the biggest skyscraper possible, deepening and strengthening so many different facets and assets of his strength before going up to the next floor. the work ethic alone is astounding

Lin Mu is chosing cores based on his resourses, but there is a pattern that he begins from the elements which he has no affinity with. So now is a question. Does he actually need to create cores for an earth and metal elements for which he already has an affinity on the innate level? From the technique point there should be all 7 cores for completing the technique and creating "balance". But what would be an effect of such cores for those elements affinity? If it would make earth and metal affinity even stronger than for the other 5 elements, than it would create another disbalance, which I assume isn't intended by the technique. Or there would be no effect at all, and he can skip those 2 cores?