I fumbled around with the same issue for months before I finally decided that the whole concept of shooting better or with more confidence using a heavier riser(typical of recurve converts)was a farse. My biggest obstacle was and still is my own mind. Carried around a Habu Death Adder that I shoot quite well for a while and then started shooting a Toelke Whip, Centaur Carbon Elite, Thunderhorn one piece Vintage, and now a Bama Expedition Hunter and so on... For true spot and stalk hunting I found the weight difference was enormous and that any lack of confidence based on mass of riser was going to be overcome! I am now recovered and quite thankful to someone who pointed this out to me.
However, if you must follow your own mind as I very much did. I think Sixby is spot on! Additionally, what I did during my spell with the mass/weight psyche was call my bowyer and see what woods or combination of wood/phenolic he had in stock or recommended for greater mass.
Just so happens that bow was recently in the Classifieds. It has a riser made of Cocobola and Ebony seperated by a accent of black phenolic. It reigns as the most beautiful bow that I ever owned and one of the heaviest...
Best,
~CB