before deciding on a specific machine it sounds like you need to do some exploring on new, larger harp with SR domestic vs. midarm vs. long arm (a good used one may be priced not a whole lot more than that new fancy domestic) vs. a sitdown. Once you've gotten a idea how they work differently, then you can start your search for one that fits your needs and budget.
A friend that is an educator for a major machine company and teaches using rulers on your domestic (plus she long arms too) said in a guild presentation that she thinks paying the expense for a stitch regulator on your domestic doesn't make sense since you are moving the quilt with your hands if you are FMQ anyway, so You are the SR!