You will want to think about finding a copy of a book by someone named Alm, Survey of European Crossbows. It is out of print, and used copies run up to $800 or more, believe it or not, but you may try an inter-library loan to get the info, as the two all wooden Skane bows are only in this book. They were both, I believe, made with yew prods, but I may be wrong. Those are push pin type locks, rather than rolling nuts, much simpler but not capable of really high poundage armbrusts. Keep it to about 100 lbs and you should be fine, And remember that a crossbow prod only has a very short power stroke / draw length.