It depends on how many users you need to support, 10-20 or hundreds, and if you will be running ASCP plans and for how many planned items. If you are not running 64-bit ASCP for lots of items, I would recommend 8 cores and 40G RAM for the DB and 4 cores and 20G Ram for the appTier. Make sure you leverage HugePages on the dbTier.
So the database has always bigger share of memory & CPU, compared to the AppsTier.
And It should not be 50/50