Fuji Hunt X-Press C41 mixing and storing?

So I'm currently processing around 10-15 rolls every week but I'm wondering if I mixed the whole 5L at once would it last 4 weeks? The bottles aren't air tight and they will be kept at room temp.

Also how much do you stir the chemicals when mixing as I don't want any oxidation....

Chances are it is going to work, see (there was a url link here which no longer exists) with Tetenal's process chemistry, and that's even a BLIX kit! If you are concerned (e.g. if this is work done for paying customers), you can get a pack of C-41 test strips, just to be sure that you are within spec.