Turnscrew is available in Dispatches From the Bunker (DftB) #44. DftB is one of the better values in ASL and Vic is currently running a sale. See the ASL Emporium and the main ASL page on Gamesquad.
It took a fair bit of research, but I was able to find a portfolio that accommodated my largest HASL map: Operation Watchtower/Edson Ridge at 30” X 42”. I am using the largest size of the Alvin Elegance Portfolio-Black-34” X 42”. I purchased it from Dick Blick in the U.S.
A series of very good recommendations are noted above.
Another stop I enjoyed is the church in Angoville-au-Plain. The story is covered in the book Angels of Mercy by Paul Woodadge (www.ddayhistorian.com).
The remains of German strongpoints are also interesting. WN 62 is one and it is...