There are a lot of variables in choosing where to have your asymetrical spinnaker sheets. The Volvo racers can fly two additional jibs along with their asymetrical chute so there isn't much room between the farthest forward jib and the tack of the chute. Having the sheets to the outside is a safer bet because there is less chance of things snagging.. It's also easier to do an outside gybe in heavy weather. It's a slower manoeuvre but these guys aren't involved in big gybing duels or multiple mark rounding where speed is of the essence.
If you have a long extending pole then inside sheeting would be better suited because there is room for the spinnaker to pass through. As mentioned it's also faster and your sheets don't have to be as long. Continuous sheeting would also help shorten sheet lengths.
On a Sandpiper I think I'd go with outside sheeting as the tack of the chute would most likely be attached at the pulpit so there's not a lot of room on the inside. Also, because usually there are only two crew, you would want an easier manoeuvre even if it takes a bit longer.
I can't see using an asymetrical spinnaker in heavy weather on a Sandpiper because the boats achieve maximum hull speed with a reefed main and jib alone. However, in lighter winds the extra spread of canvas could easily give you an extra knot or two.
And yes, I'm still riding. Here's a view of the moon over T.O at sunset, taken on New Year's Eve. The lakes a little too cold for a sail right now, but it won't be long.

D'Arcy, Shortwave