You seem to be saying to use RAW, and at the same time, that the camera is already giving far more than is needed for the end result.
The point is that if you use RAW you store the max possible info in the picture you have just taken, when you process it you may not need it to produce what you need,but, the only thing wasted is a bit of memory on the flash card. If after a few weeks you, or your client/wife/girlfriend/etc, decide they want a poster size image from it you can do it.