Whoops! I knew I should have talked about thickness!! Thickness is what determines your cooking time. Me, for most of the 1 1/2"+ steaks I buy, it's pretty much 2 hours.
That being said though, for your more well done steak, I'd be a big fan of the second hour+ being at the lower temperature - it'll preserve more of the juices.
So, in this circumstance, it'd be the first med-well steak cooked at higher temp for an hour, then reduce the bath to 130 and drop your second steak in for two hours (provided it's around that thickness). The extra time won't harm the more well done steak at all.
Great thickness/time chart on the sansaire site here:
And, of course, the Serious Eats steak guide (scroll up).
They actually explain a fair deal about moisture loss as well in that article.
Remember, when it comes to your sear, you really want those steaks completely dry. (and if you want a smidge of "forgiveness" time, you could do up an ice bath and plunge the steaks in the bag into it for 5-10 minutes before your sear, so the cook is completely stopped and the exterior of the steak is nice and cool, and not as prone to over-cooking by your sear).