Well, yes, you would smear a little royal or chocolate onto the SPS plate and set the cake tier (already on its board) onto the plate. done. If this takes more than 2 minutes, you're doing it wrong.
And let's not...
Math is your friend.
If you bake a 6" round cake, once you get it iced/fondanted, it will likely be about 7" in diameter. The Circumference will then be 7 X 3.14 = 21.98"
So, lets just work with 22"....
You can NOT deliver a cake with separations already assembled. Not with SFS or SPS system. It's just asking for a disaster. With SPS all the supports will be in the cakes and when you get onsite, you'll set the cakes...
You need a plate for each tier except the bottom tier. That one will sit on a cake drum.then you need the legs which come in bags of twelve. You need four legs per tier, except no legs go in the top tier. If you're on the Oasis site...