I don't understand what you mean. I believe my line weights are allright. If you had a heavy line on something and then moved that line into the background, wouldn't it appear smaller? And the detail lines around and in the beak and the eyes should be bold, but not around the body? Remember also lineweight can be used to separate things, and MY style has heavy influences in graffiti (which uses lineweight to separate). So I don't know what you mean. And as far as the rotary it's a stigma rotary, and they're awesome. You can go over the same spot around 8 times sometimes with no scarring or damaging of the skin. Bright yellows and white are going in on one pass, it's pretty cool. The eikon ems 300 has a special mode for it too in it's presets.
line weight is generally used to define the parts of the objects that are closer to the viewer, which it looks like you were trying to do, but your not very uniform. The feet are bolded out but you didn't do the talons which sets them back and looks odd. The head should be more of a focal point and bolded out the lines helps define focal points, but again the chest is far more bolded out and confuses the eye. The flames coming off the head have a bolded line on the frontside which gives the a very square flat look.
One other thing, careful of the bigger mags, there's a lot a gaps in your blends and you not getting up to the line. This is the thing I'm dealing with right now alot on larger pieces, they come back and the fade from one color into another is weak in the middle and and the shading isn't super solution near the lines.
Hear alot of good things about stigma, but it'll prob be awhile till i invest in rotary.