Personally, I just screwed my fenders into the drilled holes at the bottom of my Tubus (you can see clearly what I am talking about in the second photo in the thread). It's not threaded, so you'll have to pick up some locknuts at the LBS, but it saved me a lot of worry and effort. My fenders (I believe) have enough adjustability that it should work if I ever want to run fenders on my tourer without my rack (a situation I don't foresee—as far as I'm concerned now the rack is permanent).
ETA: I got my Tubus used, so these spacers everyone is talking about mean nothing to me.
ETA2: It doesn't matter, per se, which eyelets go to which accessory. I think most often the front eyelet is used for racks while the rear is used for fenders, since in most cases this would cause the least interference (rack struts go up while fender struts go toward the rear). Personally, I installed my rack on the rear eyelets to get the platform just that much lower and further back (and because the Tubus pretty much blocks off the other eyelet no matter which position it's in).
Last edited by jtgotsjets; 08-25-10 at 01:08 AM.