http://www.quaife.co.uk/shop/products/qke10e
Didn’t know Quaife did a H pattern dog box for the C64.
Yes same internals as the seq box just without the selector drum and outer casing parts
I’m looking forward to hearing more news about your C64 gears Dave. I really do hope it all comes together.
To be honest so am I but time seems to pass so quickly… 
Fingers crossed