Here on the east side of the CT River, the going rate (per square inch) for longarming is as follows:
basting $0.01
edge to edge $0.016 to $0.03
semi-custom $0.02 to $0.03
(edge to edge in center with a different border design or custom meandering design)
custom $0.035 and up
If you know the stitches per minute of your Sweet Sixteen, you can get the time if you'd be more comfortable with a per hour rate than a per square inch rate.