Uploading master data means ? you want to change the data already existed in the masters are you want to do mass actions like transfer from one PA to another PA.
if you want to do any actions then go with PA40 or you want to change the data in the already created masters then go with PA30.
LSMW is the best options for master data upload / change. first upload IT 0,1,2 then remaining if necessary in other LSMW.