I'd go bigger. I have the Original GMQ frame, similar to the new Grace Pro and I have a 17" Bailey on it (metal carriage). While I can do most of what I want to do I can't do a block larger than 12" and surely can not take advantage of all the throat space that I now have. I have to improvise sometimes. Being medically retired myself I can totally empathize with you over the funding aspect so I'd hold out for a larger frame. Then you'll know that you won't have any remorse later when you are able to get a larger throat machine.