Havent tried just putting dry rock in like that, but think that might increase the time it takes to cycle. You will just need to watch the nitrate, nitrite and ammonia levels until they drop which will signal the end of the cycle is near.
If you are near Denver, I am breaking down my 75g this weekend as I need to do some resealing to the bottom of the tank, so I will have about 20g of water that will be getting dumped. If you would like, and near by, I can set some aside for you. Just bring some buckets over.