spoiler: it doesnt work that way.
the percentages arent targets that the resource generation tries to achieve, if you claim all the diamonds in the world and mine them out except for one small area… that one small area will still only have the same percentage of diamonds it had originally (or less (*))
(*) or less, because if you mined out all the diamond… and “didnt” mine out the other resources, then when resources are put back in with the same distribution… you end up with less diamond than you started with because at the start there were 1000 resources with say 10% diamond… and then you mined out the 100 diamond leaving 900 resources, and when it inserts say 100 resources back, only 10% of them will be diamond so now you have only 10 diamonds.
the resource-spawn areas and charateristics are computed at world generation time, so “building” your own mountain ontop of some unbeaconed land isnt going to change the way resources generate into that unbeaconed area beneath your new mountain.