Andrea
I pour syrups on while the cake is still quite warm, very soon after coming out of the oven. But I've done them cold too, so you'll be fine either way. They sink in better when the cake is warm, IMHO. With the berries you could flavor it with a touch of chambord, that would be very nice, or Grand Marnier, even nicer! If you don't want to use alcohol in the syrup, some orange and lemon juice and some zest in the syrup would be a nice compliment.
If you're serving with strawberries, have you thought about using a gelatin stablized whip cream (like that used for Black Forest Cherry Cake)? That would be a nice combination with the cake, syrup, berries, and whipped cream.
STABILIZED WHIPPED CREAM
1 tsp. plain gelatin
2 tbsp. cold water
1 c. whipping cream
3 tbsp. powdered sugar
1/2 tsp. vanilla
Add gelatin to cold water in small pan. Set this over boiling water until it is clear. Do not stir. Cool to room temperature. Meanwhile whip the cream until it is medium thick. Pour gelatin mixture into the center of cream while mixer is going. Pour in the gelatin all at once and continue beating. Add powdered sugar and vanilla. Beat until cream stands in stiff peaks. Use as frosting for cakes or dessert decoration.