Hi darkosaric, i will post some links that have helped me very much concerning split grade printing.

It all started with an old forum post here on apug.


page 3 has a post by bob carnie (post #26) explaining in detail a similar, but different approach.
here is les mcleans very well detailed with photo examples approach


^ this one is awesome, it has helped me out so much.

The difference between that and what i do, is i use 1/3 or 1/4 of a sheet of paper. when i use a 0 filter, and when i use a 5 filter. After i pick a combination, i do a whole print as stated, followed by a hopefully final print that is dodged and burned.

While i became proficient at guessing which filter i needed, with what times, the above method almost ensures, that you won't waste more than 3 (4 if you mess up) sheets of paper.