Always best 2 get it mixed up like u say mate get a better match
Have u not got the original code from what the car was sprayed?! or might be worth askin where did it for it?!
Either way mate where ever u get to mix it will have all the colour codes etc for pretty much most cars so just ask them when u go down there
If u got a part of the car u can take down with u aswell they might be able 2 use it to get as good a match as they can