I would agree with dasBlute, use a lower contrast filter to burn in highlights, makes sense if you think about it. Also, sometimes it's better to use something a bit higher than 00 for burning in, you will get better "shape" from shading with a 0 or 1.
I also go for the low filter exposure first. Remember that even the 00 filter puts exposure in the shadows (do it by itself to see how much), the 5 is adding to something already there, so you can't see the composite exposure in the shadows till you do both. I don't think the 5 adds much to light highlights, which is why I go for the highlight exposure first.
I ususally do a test strip with 00 or 0 (if I want more separation, or shape in the highlights), then pick one and do a print with that by itself. Then make a test strip adding the high filter. Then make the composite.
One thing I find - the high contrast exposure is almost never as much as the low contrast, in fact, usually considerably less. And I start with just enough to make a black somewhere. Then add more of the high filter if I want the darkness to increase coming up the scale toward highlights. Or use a 4 or 3 as the high contrast exposure to make the mid and 3/4 tones darker as well, preserving the highlights.
I find that split printing takes much longer than graded, but I'll "never go back", too much control I can't get with graded.
Hi George, thanks for the tips, I'll definitely give them a go! Up until a few months ago, I had never even heard of split grade printing. Have to say, it's an excellent tool, and I'm really enjoying the experimentation.