I think the reason for the cranked tailboom has little to do with aerodynamics but simply to keep the tailboom clear of the rotor blades on wind up and more particularly on shutdown. Even with the cranked tailboom, I've seen a blade get frighteningly close to the boom shutting down in a gusting wind, and every now and then, one of the droop stops wouldn't go in which made it worse.
Unfortunately the problem of Gnome engine "rundowns" is complex because of the interaction between the engine (compressor stalls) and the engine computor and its associated signalling circuits which made diagnosis not so easy. Having had one as late as the '90's (this was a compressor stall) in a privately operated ex RAF Whirlwind, the problem never really went away.