Honestly I would recommend you do just one portfolio, in A3 with minimum 14 point text. Use it for both print and PDF so that when you update it in the future you don’t have to update two portfolios. Just don’t fill pages so much as if you would in a printed portfolio to make it cheaper to print, keep pages simple and clear so that you can flick through them like people do with PDF portfolios. Just have something interesting to say about each page and keep moving so that you can keep the interviewer visually and cognitively engaged. Also put SOME information on pages that you will say but also leave some out so that you can go through the same portfolio in an interview and they will understand the project and you can add more to it that you kept out of the pages.
I hope this helps, I am sure people will both agree and disagree with me on this.