At the bakery were I used to work they used Dreidopple compounds. I use Braun(i think) and I have used Hero before too. When I make a fruit mousse, aside from using the puree, I add a dash of the compound(it really intensifies the straw. or rasp. flavor, kinda giving it a punch).
You don't need to know baker's percentages for mousses and fillings, just for breads and cake baking. It is a useful thing to know, it helps you understand the difference in textures/flavors of any baked good and how to correct things if something goes wrong. I taught myself and eventually got used to doing it automatically. I really recommend you get Professional Baking, 3rd edition by Wayne Gisslen. This 3rd edition which I just got is so much better than the older edition I have. Le Cordon Bleu collaborated with him and made the recipes and styles more "hip". I haven't tried most of the recipes yet(the muffins really **** and so do the quickbreads) but use the percentages as guidelines and his frozen mousse recipe is very good. Go to a store like Barnes and Noble and check it out before you decide to get it. That's what I do --- I just got Spago's chocolate book and Bread Alone.
Yeah, most of the mousses I get asked to make are mostly chocolate. Strawberry, raspberry and lemon come in second. That's why I want to make samples for the sales managers to try. I made a white chocolate passion fruit mousse today which was pretty tasty(I just added a dash of the fruit puree to my standard white mousse but increased the chocolate a wee bit to compensate for how tart the passion fruit is). I don't get fresh exotic fruits since they are expensive and I'm not familiar with the seasons, so I just get Perfect Puree products. Since I've never really had a chance to work with more exotic fruit, now's my chance to try out some recipes and hopefully standardize them.
Here are the recipes from the book:
Fruit puree 8-10 oz.
sugar 4 oz.(adjustable)
lemon juice 1 oz.
gelatin 1/2 oz.
water 5 oz.
Cream 12 oz.
Basic Bombe Mixture(Frozen bombe)
sugar 8 oz.
water 2 oz.
eggyolks 4 oz.(6 yolks)
Flavorings: melted chocolate,liqueur,instant coffee, praline paste, fruit puree.
Heavy cream 12 oz.
Boil sugar and water to 240F while whipping yolks until light. Pour syrup into yolks. Mix until cool and thick. This mixture will keep covered and refrigerated for up to a week. When ready to make mousse/dessert, proceed with next steps. Stir in desired flavorings into pate a bombe. I add gelatin if I am not freezing the mousse. Whip the cream to mediumfirm peaks and then fold into base mixture.
This is just the gist of the recipe, it's a bit more detailed in the book.
Bighat has a good tip on the gelatin.