Polymer draggable with interact.js / shadowDOM selector

I am attempting to use the interact.js library to create a draggable Polymer event. I know there exists a core-drag-drop element, I would like to use interact.js. I am attempting to get the first example working by passing in a class to the interact object.

interact('.draggable').draggable({....

This doesn't work in Polymer as it has to access the elements shadowDOM. I have tried the following selectors:

"custom-elem::shadow .draggable"
":host-context(.draggable)"
":host(.draggable)"
"custom-elem /deep/ .draggable"
"drop::shadow .draggable"
"custom-elem::shadow .draggable"

All return null.

I also attempted to assign and pass a reference to a single object which has the .draggable class:

var x = this.shadowRoot.querySelector(".draggable");
interact(x).draggable({....

This does not work as well. Any advice?