It's almost the same as HG/SS actually. You need the Coin Flip app and you use coin flips to determine your initial seed. However coin flips do not advance the main RNG. It advances the RNG used for egg PIDs instead but since they both have the same starting seed it works out.
In Platinum the even/odd thing is a little strange... I've hit both at times and changing the year or inserting a GBA Pokemon game didn't have any effect.
In Platinum the even/odd thing is a little strange... I've hit both at times and changing the year or inserting a GBA Pokemon game didn't have any effect.