as pakled mentioned, bryce imports everything at one size and then you'll need to scale the figure to fit. It's basically a guessing game as you scale so keep an eye on the figure size in relation to the landscape. It won't matter what you export or how you export it (directly from Poser or through D|S), Bryce will still import it at the same size. Once in Bryce, select the body group (includes all the body parts, clothing, etc.) and scale it using the scale tool or by pulling on the corners of the bounding box.