I agree with previous poster. You can get away without the concave washer in the back, especially since this is a rack and not a brake. Another possibility is to use a fork crown daruma instead of the rack bolt to mount the fender. That will only gain you a little space but it's something. Additional advantage is that it looks neater and it's a little easier to get the fenders on and off for sunny days if you ever need to do that.

Lastly, I'd guess that those racks are made from 304 or similar steel, which is fairly ductile. It wouldn't bug me to bend that strut a little bit if needed. However, no harm in a slight back tilt, as others have said. It's really pretty much level enough right now.