Yes, you can expose for the bottom as you have already done, then put in the 0 filter and burn in the top.
Split grade printing works slightly differently. You expose the whole negative on the 0 filter, start with a test strip, and determine a proper exposure for the highlights. Then expose the whole sheet for your highlights only, then put in the 5 filter, and do a test strip on the same sheet of paper. When you determine the proper exposure for both, you'll expose the next sheet with your 0 filter exposure, then change filters, and expose with the 5 filter. It's pretty easy, and you'll get the tone you need in the highlight area.