Instagram Feed shortcode absolute positioning

Happy 2015 everyone!

I’m using the Instagram Feed plugin by Smash Balloon which conveniently gives me a shortcode to display different Instagram feeds on a WP post or page. It allows me to display them in columns but I would like to arrange them exactly where I want, for example: one in the middle 200x200px, five surrounding it 150x150px, another to the top left of the page 100x100px.

And can I do it without stripping the entire WP CSS?

I’ve tried adding this CSS using the Jetpack CSS editor but because it modifies the div tag, obviously I screwed up the entire theme of the website.

Hope someone can point me in the right direction. I’d be happy to RTFM or any tutorials if you could point me to what I should look up.

Many thanks!