If he rounded the gears, he may have setup the diffs to have the least amount of play ( probably 1 or two shims ). Brand new that will happen. Best bet may be to run three from the get go and don't worry about it.
I think Tim is away right now, You should ask for him when you all MRC as he knows the most about the vehicle and will get you what you need. With the rollout of the Pro coming up, I hope to see academy getting more stuff produced. Good job on the finish however!