Not sure why you want a pair of shocks to preserve the look. Series C had 3 boxes (2 spring, 1 damper) and Series D had 1 spring/damper unit as far as I know. Call it a modern D and use a monoshock cantilever rear end. I don't know what Terry Prince uses, but I don't like the idea of 2 spring dampers that close together - don't know why and I'm off on holiday, so I don't want to tax my brain working out what I don't like about it - I think it's the thought of two dampers with separate adjustment not working in sync.