Fun facts about bearings...
If your wheel has a lot of play and that is why you are going to re-pack the bearings, then just order new ones. The current ones are probably too worn and oval now. Not all loose bearing will come in cages, but yes many newer sets will.
If your wheels feel solid but just gummed up from old grease then you can most likely use the old bearings with some fresh grease. Just get them super clean.
I recently learned of a test to figure out if your bearings are still round. Place them in a smooth bowl and roll them. If they are warped at all you will hear them jumping a bit. If they are round still they will roll smoothly around the bowl.
Just use your previous experience and make sure to remove the axel carefully and do it over a towel so they dont go bouncing all over.
You could always go a sealed bearing conversion too.