1. You don’t want it to grow? It shouldn’t by default, the issue is that your image isn’t wide enough to fill the container. Reducing the width of the post container should fix this.
2. This CSS should do it:
.wp-show-posts-entry-title {
text-align: center;
}3. Not sure what you mean here? You don’t want it to go down onto two lines?
4. Reduce the padding value inside your list settings.
5. Some CSS:
.wpsp-load-more {
text-align: center;
}You can change the text with a filter:
add_filter( 'wpsp_ajax_load_more', function() {
return 'Load next';
} );