I use the manual way too, only problem i face is i want to replace A theme UI on B theme by modifying the theme json file, but i end with the default theme UI.Fantastic app mate, well done.:good::good::good:
i usually do i t manually or simply mod the single apk(to keep only few parts of the theme x app)
Sorry Dr.Ketan if it is out of contest, but I don't want to use the stock UI, thats why iam asking alex74 here