If you're going to be throwing the lasso from one distance only, probably one of the easiest (not necessarily best) approaches would be to use an animation. Keep in mind that this approach only works if you're doing the lasso-throwing from one distance only.
I really would reccomend you using animations, it is easier and cleaner, you also can use a gui texture
as a sight point to locate your opponent and to catch it with the lasso.
Remember that the succesfull games always care about the user experience, this is the difference between making good games and making addictive games.