Dimensional changes require that custom CSS be added to the builder themes CSS section.
Visit Change the Image Size or CSS for a Product Builder Product for complete instructions.
Here is some sample CSS that can be added that will enlarge the height and width of some of the builder elements:
.shappify_product_builder .choices {
height: 225px !important;
}
.shappify_product_builder {
height: 800px !important;
}
.steps_body, .option_image_pane {
height: 800px !important;
}
#option_image, .spritespin-stage {
height: 450px !important;
}
.choices {
width: 140px !important;
}