CROWS IN A GROUP PAINTING (REACT )

This is the finished crow collage.  I decided to put a mat around the piece which I created with Bass Wood and painted with acrylic paint because I wanted the composition to be tight.  I had tried an earlier version where there was more space around the group of crows who are looking at something, but had to wipe that composition off.  I wanted the viewer to guess what the crows see.  I guess I personified them by including some words in the collage ," I'm not a size two", " Stop me if it's too much for your eyes" and the simple word "react".

Now for another problem.  I read a recipe online by another artist about a medium they use.  I decided to give it a try.  My palette of oil colors are mainly Graham Oils, which contain walnut oil.  The mediums recipe is 1 pt stand oil, 2 pts linseed oil, 1 pt turp.  The problem I am having is the painting will not dry.  It has been two weeks since I finished and it's still very wet.  I have to admit it's the first time I have used a medium  and I really like working with it.  I did try and us it sparingly into the oils; but perhaps the mixture of Linseed Oil with the walnut oil is the culprit.  Anyone out there have an idea if this is the cause of it taking so long to dry?