This is probably over stressing but I thought I'd ask some veterans. I have recently started riding to work and decided a rear rack was a step in the right direction (tired of carrying heavy locks on my back). After gathering the courage to attach stuff to my relatively new bike and risk scratching the paint I screwed on the rack. The instructions say that it should be level but the length of the twisty struts (or whatever you call them) only allows me to install the rack so that it is slightly tilted toward the bike (front lower than back). It looks like I'll still be able to put stuff on it (i.e. not at too much of an angle) but I was wondering if there was likely to be any unanticipated problems as a result of not following instructions to the letter.

You're fine.

Yes, you will probably be fine.

That said, it is sort of an aesthetic pet peeve of mine, so I look for racks that can be adequately adjusted to keep them level.

Well, if it gets troublesome, there are always longer struts you can get at your lbs.

Where are you attaching the struts to? If you're attaching them to the seatpost bolt, then you could use "P" clamps on the seatstays and move them back a bit.

Attaching to seatstays.