Actually, if you think about it, a GT40 isn't strictly RHD in the sense that a British or Down-Under car is, because the gearshift on a GT40 is still righthanded, not lefthanded. I would have much more trouble getting used to a left-handed gearchange than I would just sitting on the "other" side of the car but still doing everything the same. When I bought a Mini, which was recently, I decided to get a lefthand drive one. It makes tolls, etc a lot easier. Passing is not an issue as you can't pass anything in a Mini. But my GT40 is going to be righthand drive- because the man who is building the tub, who is a purist, refuses to build anything else...abd it will look more authentic that way.
By the way, Jim, I like your passing instructions, can't wait to try them out.