I think i've pushed the limits, maybe not. Here's what I did after chasing a ring and roughing out the shape. 61" long, 1 3/4" wide for 12" tapering to 1/2" knocks. ~1/2" thick. Cut out a caul in short order and made the stave bend. Now, here's the scary part, I built the curves in my caul using dimensions from my a glass longbow I have which i would consider to be extreme D/R. Think she'll blow? How does a guy go about tillering something like this (besides slowly)?