JulieM,
Each frame has it's own specific limitations. You have to choose by what you will get the most use out of. Grace has multiple sizes from craft to king and both wooden and metal models, for example. I have an original GMQ from grace. It will do a king size up to 104" wide and of course the length is then unlimited. The O-GMQ was originally meant for use with a home sewing machine or maximum throat space of 13" (tried that and will never do it again!). I added the new carriage upgrade to my frame and now have a 17" Bailey on the frame. I'm still limited by my frame however and can only do up to a 12" block on point. I'm going to have the arms that hold the rollers modified and then I'll be able to make use of the full length of the neck of my machine. A new Grace Pro frame would eliminate all of those issues. The point is...check with the frame company prior to buying the machine to find out what the specs of the machine have to be to make it work on that particular frame that you are considering. Good Luck!