In a medium bowl, beat mascarpone cheese, yogurt and 4 tbsp sugar until smooth. In a separate chilled bowl, beat half and half until soft peaks form. Add remaining 2 tbsp sugar and beat until stiff peaks form. Carefully fold whipped cream into cheese mixture; set side. Combine nectar and rum in a small shallow dish. Quickly dip each side of the ladyfingers into the mixture. Place half of the ladyfingers in the bottom of a 8-inch baking dish so they fit tightly. Spread half of the cream mixture onto the ladyfingers, then top with peach slices. Repeat ladyfinger and cream layers. Cover tightly and refrigerate for at least 6 hours or up to 24 hours. Sprinkle with almonds before cutting into squares with a sharpe knife and serving.