The only thing coming out of my studio that may be cracking up is me (wise cracking of course). Seriously, I have not been using this medium very long but I feel that the addition of alkyd resin will more than compensate for the inequities of almost any additional ingredient. I am using it with W&N colors, which use more conventional oils as their binder. M. Graham & Co. makes a line of paints using walnut oil and I haven't heard any negative info. Their site is
http://www.mgraham.com/ You can contact them if you have any questions. They are very helpful.