Optimum Vector and ACA Settings /workflow for compositing on a 4k Premiere timeline.

We have created a series of characters in illustrator on a 1920 x 1080 artboard.

When we bring them in to ACA the resolution says 100% but when I render the character and bring the video file into Premiere the video is about 50% and scaling it in Premiere results in poor resolution.

I have the Puppet setting set to 400% (High) resolution.

My solution to this problem is to scale the character to 200%.  This works BUT, if I want to scale it to a 4k video format I can't work on the image in ACA at 400% scale.

Is there a workaround that will allow me to output the vector images at a larger size. 

(I have tried the 'render as vector' and aside from having to redo the artwork to get rid of double pupils it doesn't seem to make a difference in resolution.

Can you tell me the optimum workflow for compositing in a 4k premiere timeline?