So I noticed a thread tonight that was on how to get into only random Oculus or whatnot [hasn't panned out], and it got me thinking, I'll post my method for farming these.
Since you can do multiple instances of the same instance with the random system in one day, this is particularly useful if you are mindlessly trying to get your mounts. All you do is queue for a random. Cross your fingers, if you get the instance you want, great. If you don't, just ask your group to vote kick you. You shouldn't get the deserter debuff, and you can requeue. I often did this during Hallow's End by saying I meant to queue for holiday boss please kick me, but you can make up any excuse really. Helps, of course, to be a tank; I was getting into a new random group every few minutes when I did it.
I used this as of Hallow's End, got my blue proto. If something has changed and this doesn't work now I apologize.