In the case of “Smokebomb”, the extra space behind the animation was filled in with copy/pasted duplicates of the design to flesh out the space. You may find similar ways to finish your animation.
Once you feel satisfied, create a .285” circle in the center of your disc (for the turntable spindle) and return to step 1 with your new custom phenakistoscope.
There are a number of fun little visual tricks that can be pulled with phenakistoscopes, such as setting up separate rings at different frame rates that appear to move forwards and backwards on the wheel or warping a filmstrip with polar coordinates. The medium can also be carried from print over to a laser cutter for the extra analog power of a wooden disc. No matter what, it should certainly give you an appreciation for the roundabout route that motion pictures have taken to achieve their current form & the bygone optical tools of the past.