I like the Old School look of flames but the "bad boy" look of chains would look good too. You would need a good painter to make them look real though.
have been kicking the basically the same idea around that you have...and thought that a good smoke effect would not take away from the bike's theme I have ...but definately look better than the stock flames
On 861 I'd take out the dark outline. The one you posted... I'd try to make the blue flames a little more transparent. I feel your pain...went back and forth on this same thing for months.