Charles,
Here's what I did,
When I started my cuttings in the RR cubes I potted them up as soon as they broke bud or when they had a fair amount of roots.
I still placed them after they were potted in deep containers and misted them everyday while under the lights. Then slowly I moved them out into the open.
They weren't watered much but I did spray them everyday and sometimes twice a day. Just don't let the cubes dry off completely. Those that failed were mostly due to fungus gnats.
I would suggest you try them with the more common cultivars as a learning tool till you get the hang of it.
This would be the perfect time to try this so by the next rooting/growing season you would have packed down and ready to move up with the more rare ones.
But believe it or not, there are others that took this method and produced much better than I did.
Confidence can be your best friend. You will be fine.