I haven't read all the posts but I agree with Neesie, if you are happy with the machine that you already have just cover the feed dogs. I free motioned for years with the feed dogs covered on my Kenmore. I used the lid of a margarine (or whatever) container cut to fit and taped onto the bed of the machine. I didn't bother making a hole for needle. It did that all by itself when the needle went up and down. The advantage is that you have only a little round hole, not that larger oval one on many plates, which stops some of the problems one has with the thread tangling up in the bobbin area.
Although I have not personally tried it, there are some free motion quilters who insist that one should not drop the feed dogs to free motion quilt. They say it works better for them.
Good luck with the next step in your quilting journey.
amh