1. When you do 'second pass lith' as Tim Rudman calls it, you start with a print that has been printed about 1/2 stop too dark. The reason for this is that if you start with one that is perfect, bleach back, and redevelop fully, the print will look pretty much the same as the original. To get the crazy colors and the interesting effects, you must stop before the print is fully redeveloped, hence the 1/2 stop over-exposure in the enlarger required when you make the original silver gelatin print.
2. For second pass lith you bleach the print back as far as you can, almost to paper white.
3. For toning, it's a matter of preference how far you bleach back. The farther you bleach back, the stronger the toning will affect the print.
4. For toning - try diluting the bleach like 1:50 from the stock solution, and get your bleach from the same source every time so that you don't have variations in the results, making it a guessing game how much to bleach.