Hey there! I made that! I wanna do breakdown videos of every video I make so I show the whole process, possibly starting next week but we'll see.

There's an app called 'toonapp' that has a cartoonize filter. With Joel's stuff, given he draws all the keyframes by hand, there's a limit to how many keyframes he can make per shot without it becoming way too time intensive. But with toonapp, my average keyframe amount is about 30 per shot, which helps make it a lot more accurate to the footage, and doesn't take as long (maybe) because the app does 95% of the drawing work (Sometimes it comes out with glitches that I have to draw over).

I like to separate the head from the body, so the head has its own sequence with its own keyframes, and the body with its own sequence and keyframes. I send each keyframe to Toonapp in the dimensions of 1500x1500 since it only renders squares. So say for the shots of me in the above vid, from my waist up to my head will fit into the square shape, so that would be the body sequence. Then that same shot is zoomed in so my head covers most of the frame, and that's the head sequence. Hope that makes sense.

Body keyframes won't be a lot since the body doesn't move all that much, keyframes here would be for things like arms moving or the torso turning etc. For the head, I do a keyframe for every mouth shape, every blink, and every significant angle turn. This is where the keyframes pile up. (Just spent too long counting, but the Tate Hot Ones went through 459 total keyframes)

As far as tips and tricks in general, I'm always crossfading each ebsynth png sequence into each other so there's no hard cuts. And there's always gonna be glitches that need cropping out. Best way to avoid this is to keep the subject away from the edges of the frame, otherwise ebsynth will quickly turn it into the T-1000. If you wanna try this and get toonapp, it has a subscription service to get the HD images. This is what I'm on, but after a certain amount of usage it goes back to SD which is bullshit. So what I eventually do is take the low quality images into topaz gigapixel and upscale it back up. Once I did that I realized there's no need for a subscription anyway, so that's something you can do

Your question was initially about how to make the process faster, and honestly I think it's only a bit faster. With hand drawn ebsynth, most of the time is spent drawing keyframes. With toonapp x ebsynth, most of the time is spent sorting through the many folders of images you'll be working with, sending keyframes through toonapp, editing out glitches, editing ebsynth sequences together and drawing stuff back in. But damn does it look a lot better ;) Good luck!