Welcome to the forum, Derek.
Could you please modify your profile to let us know what equipment you have to make this ellippse?
I would use your Rockler jig to make a male template 9 x 17 and then use template guides with plastics spacers to make smaller templates.
Bobj3 may be along to help you here as he has posted on this topic many time and has also modified his Rockler jig to make very small ellipses.
I don't mind if other members disagree with my comments.
I don't profess to know everything, and I may learn something new.
"Never attribute to malice that which is adequately explained by stupidity."