Use an "extension" of 1.25 diameter basin pipe (visit your local hardware store's plumbing section) in the eyepiece-holder to get your eye farther away (yet centered) from the secondary reflection. The farther your eye is from the telescope, the better/more accurate your sightings will be.
You can make a "dummy" eyepiece (from wood or an old high-power eyepiece like you get with those Tasco-type reflectors). This ensures that your eye is centered in the eyepiece position when you finalize your collimation.