Hey guys, found some good news yesterday. There is a Squardron Signal Publications book about WWII landing craft. In it it states that the only difference between the 3 & 6 is 6 feet in length, the width is the same. Makes me even more excited about the upcoming release(s). Send me your email address at 
[email protected] and I'll send you the scale drawings I have for the monitor. 
I scaled them down from some plans I purchsed at The floating Dry Dock, I also purchased plans for a PCF, but haven't scaled those. I think the original plans are 3/4" to 1'  they also had other BWN plans, but I can't recall all of them, I think there was a PBR MK I. ??
I was fortunate enough to be able to print the pages from John Carricos web site, where he has detailed photos of his build for the ATCH. Unfortunatly I printed to a B&W printer, so they don't scan well. Hopefully he will have his new site up and running soon. He also talked about publishing a book on the BWN monitors. This was a couple 3 years ago though.
S~