This thread is making my head hurt. You guys are waaaay overcomplicating a simple thing.
1- Do the 00 first. Pick the time that gives you the highlights you want.
2- Expose your next test strip with that time and the 00 filter then without moving the paper
switch to the 5 filter and do your test strip on that same paper. Pick your exposure to get the shadows where you want them.
Easy Peasy. That is about all you need to know so you can stop reading here if it suits you.
Occasionally if you are doing larger prints or using grainy film, the 5 exposure can degrade the highlights. This is because you are actually enlarging the space between the grains. If you notice that happening, back off your 00 exposure a little.
Starting with the 5 exposure is a mistake because the 00 will also add density in the shadows.
Varable contrast papers typically have three layers that vary in speed and frequency sensitivity. The "soft" layers are slower layers and green sensitive. The "hard" layer is faster and blue sensitive. Some papers have a bump in the middle because of this which is why some old schoolers don't like Variable Contrast papers.
And yes, prints done with a single filter and prints done by split printing are basically the same if they are unmanipulated. Split printing gets you where you want to go a lot faster though. People that only use one filter are trying to hit a moving target since they are dealing with time and contrast together and changing one changes the other.
That is about as super simple as I can make it. Hope that helps you.