Rear disc with parking brake for 15 inch wheels

[Zanie]

This is for my mini tubbed 56 Chevy and its got some vintage American CP200 15 inch wheels so the brakes can't be too large.
I've currently got the oddball set up of 11 inch 79-81 trans am rear rotors with the caddy seville calipers. The parking brakes are those hokey GM ratchet thing.
It looks like this (not mine, but it looks the same)


yes, the calipers and small pads don't fully utilize the rotor.
The questionable parking brake was just fine when I was running an automatic transmission and I never really "needed" the parking brake.
I'm switching to a T56 this time around so I will need a functioning parking brake.
I'm running a ford 9 inch rear with the big torino ends and the GM 4.75 bolt pattern.

I could go with the bigger GM caliper to use the whole rotor and add a second parking brake caliper.
I considered a pinion mounted parking brake, but I don't think I have the floor clearance.



easy bolt ons or lots of fabrication, I'm open.
Any suggestions would be greatly appreciated.
Thanks.