F&T, the wheels are 406. I used "nominal 20" in esteemed Sheldon's gear calculator, since there wasn't a selection for 37-406 (1.35"). A 53/12 combination on a 700c with 175 mm cranks is 116.1 gear inches. The 53/9 combination on the Mauna Kea feels "not quite 53/12, but taller than 53/13" on a 700c.
That sounds about right - with Comets on 406s I reckon a 53/9 will be about 112".
Let us know how that Capreo cassette gets on. I am getting rid of my Birdy and will prob go for a Capreo upgrade on a single ring/20" machine.