The FRC ckt is just a high cut. I would order something in the order
of a xxx/35/15 Discovery 2. You really just need a flat response
that is inefficient in the highs. I've been using the D-2 since it
came out for reverse slopes. I notice that Starkey has a
reverse-slope response in the new spec book. Give a hollar to
Chiquita Mayhew at Starkey Mpls for more info. As an aside, it would
never occur to me to fit a BTE on a teen.