On some of the early carbon reinforced kits, the spar receiver holes in the bulkheads were not drilled right. I had to fill the stock holes and re-drill new ones to get the proper anhedral. I was lucky enough to get a tip about this from the Austin Gang (Dan, Doug and Roger)

The best way to check this, is to install the spar receivers onto the bulkheads before they are installed in the fuse and check them with a straight edge.

This was corrected in the later kits.