Mike Bull wrote:We could make do with one of those dinky-sized cut-down blades that the ground-running Merlin guys use, though perish the thought that we'd ever make the Fairey Barracuda look daft!

One of our technical sponsors, Oliver Valves, has a Merlin-on-a-trailer set-up with one of these cut-down sets of prop blades to which you refer. I watched it running last year and it runs very well indeed with it - even up to full power.
Such a set-up would, however, look well-weird if the engine was in an aircraft ...
Spare a thought for the old "Barra" - it wasn't
such a bad aeroplane! With the wing-folding mechanism in full working order, yours will look simply amazing.