yes g stands for Grams
Im almost positive the amounts are right
A silpat is a silacon baking sheet, they can withstand very high temperatures and nothing sticks to them, we use them to line pans just like you would use parchment paper. Demarle sells them www.DemarleUSA.com
A placquette is a thin piece of chocolate it can be any shape, sometimes I make them with a design sometimes just plain.
btw this is the same cake we made for a bday party for the mayor of Chicago last year.
enjoy
Nancy