All of the ones I've seen do not require you to access the rear of the bolt. The nut on the back side is a big plate floating in a track. Just loosen the allen head slightly and lightly tap the bolt with a hammer into the correct position before tightening the allen head fastener. The trick is holding it in position as you tighten as it often wants to move a little as you tighten. If you get it too far back, the door may become very hard to open.
Fred
Fred & Vicki
St. Augustine, Florida