Dear Troels,
I completed the build of the Revelator 851s in late December, using the complete kit from Jantzen (Michael was very gracious to work with). Due to your excellent and extensive instructions and photos I am proud to say these turned out better than I expected!
I acquired a new router for this project (the Dewalt DW621, very nice!) along with the router guide from Jantzen. Due to the difficulty procuring bitumen sheets in the U.S., I used 2 layers of rubberized asphalt flashing sheets glued together and to the baltic birch plywood with vinyl tile adhesive. This totalled about 4mm in thickness. I believe it works well. I used stainless steel hardware to aid in attaching the heavy inductors to the boards and the boards to the speaker box.
I am very impressed with the sound of these speakers. I have been using a satellite-sub arrangement for a long while, and the bass extension from the 851s greatly enhances the soundstage in the room. Also the resolution is outstanding, but the high end is not overly bright. The midrange is a high point!  I am really loving them! Thanks for your dedication to the DIY community and help allowing me to build some of the best speakers I have heard. 
Steve in Texas