Who cares if more than 5 grams a day goes to waste? At least you'll be confident you are at saturation. Supposedly taking more than 5 grams in one sitting will result in a lot of it going to waste, but if you break it up throughout the day, I don't see a problem with it.
Yeah, no point in taking time off from it either, considering the stuff is dirt cheap and you'll only be cheating yourself from the benefits of cre usage. From what I've read, your body does NOT become dependent on cre supplementation either, so why take time off?
Taking your cre with carbs is supposed to increase uptake a bit.