(http://i868.photobucket.com/albums/ab246/yornoc/tipandapp024.jpg)
Could the belly of the riser just above the shelf be cut forward to line up with the back of the shelf without weakening the riser too much?
Andy it all depends on how thick the window is and how deep the thumb groove is cut. The bowyer that made that bow designed it that way because he was evidently haveing trouble with cracking at the back of the shlf from compression. That is the most common place for a riser to break due to compression. Its one of the reasons I build I beam risers. God bless and good luck. Steve