As an artist I would do/demand something like this:
-I need a clear job description; what models, what complexity, what maps (diffuse, specular, normal)... do I need to rig them (x2 money) or animate them (x6 money)?
-If I would have to design the models too that will take time (money) also in addition of the modeling and texturing
-I would NEVER do anything for royalty promises only - "you'll get x% of the sales when this gets finished" is a sure way to get nada. I would want fixed pay for the assets I make and maybe small royalty.
-One way to do things is also per hour basis, but that would not be the best choice for you.
-I need a clear job description; what models, what complexity, what maps (diffuse, specular, normal)... do I need to rig them (x2 money) or animate them (x6 money)?
-If I would have to design the models too that will take time (money) also in addition of the modeling and texturing
-I would NEVER do anything for royalty promises only - "you'll get x% of the sales when this gets finished" is a sure way to get nada. I would want fixed pay for the assets I make and maybe small royalty.
-One way to do things is also per hour basis, but that would not be the best choice for you.