What would be a good mix between the workers to make a good amount of profit? I'm thinking of a mix between maple logs and coal. Would this be viable?

Technically the best steady profit is 100% Raw Fish and 50% Mining, getting you about 130k a day (assuming you have 100% Approval Daily)... But if you want to chance it, I do 100% maples + 50% Raw Fish, for the chance of getting an expensive seed.

 

 

 

http://runescape.wikia.com/wiki/Calculators/Miscellania

Uncooked fish are the best, so put them on 100%. If you think you can make more with maple logs because of seeds, go for it, but with just the base resources, put coal on 50%.