Hi Robert sorry no one responded before now. I’m not that good at math so I’m going to refer you to NBully’s mix calculator he posted. You can download it and calculate any mix ratios you like. Other than that, not much I can say since I have a not so easy time myself making my own mixes 
Here’s the link to the thread: Mix Calculator 10.0
From what I understand he also has a system for $10 using Google docs that is available for any OS. I believe the link above is based on DOS. While I have not used his new one and therefore cannot personally review it, I can say with some certainty the other one is excellent. I have my own developed by someone else so I’ve only used a few times but the results were on par with what mine said. The paid one can be found by going to this thread: Online Mix Calculator