I did some FMQ on my Singer 66 Red Eye, no stitch regulator. However, I did a lot of practicing before going to work on the actual quilt. It helps to have a quilting foot (I used the one that goes on my embroidery machine). It goes up when the needle is up, and down when the needle is down. This helps somewhat in getting stitches close to the same size. Mostly it's a matter of coordinating between moving the quilt around and the machine speed.
A quilting machine with a stitch regulator would obviously make this much easier, but it can be done on a regular machine. I've even seen a video of a lady doing free-motion topstitching on a treadle, making purses. That sort of talent only comes with LOTS of practice.