well, I had to take my rear tire off 5 or so times on tour (flats) if the rack was flopping around the whole time it may have annoyed me. although I did have to take everything off my rack to do this anyway , so on second thought it may not be too bad. And with MTB tires, I dont think flats will be as much of an issue. (?) If everything else lines up that well, then Id say go for it. If and when you have to change a tire you just deal with it. The racks "leg" where the skewer is going through is made of aluminum? this may deform or squish under the pressure of a tight skewer plus a heavy load and its associated forces. I think on my rack this flattened part doesnt provide the surface area to match my frame or skewer.. this combined with it being made of soft aluminum, makes it suspect.. Id try it but watch it. ride for a week or so before leaving and check it everyday.
I think you'll have to try it and see.
~Steve