Margin and reorder for pieces in masonry portfolio

two-fold question about the sydney portfolio

1-i’ve tried isolating the style to add a margin around the thumbnails but am not having luck selecting the correct one. has anyone else tried this? if so, would you share?

2-i’ve got almost 50 pieces for the projects section. i was wondering if it is possible to only show say 12 pieces that are randomly selected from the entire group. as it is now, it seems to only pull the last 12 that were entered and i’d rather not show all 50 images as it’s overwhelming and WAY too busy. do i just try to reorder the projects or is there a style that can be added to the shortcode to tell it to pull 12 random images? also, i am hoping that it will still access the entire library of images so that if a filter is selected, it will pull all of that category whether the image was originally displayed or not. does that make sense? if this is not the functionality of this extension, does anyone know of another portfolio plugin that works this way?

as always, any suggestions or help appreciated!!