On a cruising boat the asymmetrical spin would usually be tacked at the bow. The Dehler 36 I was sailing on has a removable bow sprit to tack the asym to for close reaching but also has a pole for flying a symmetrical spinnaker. This is the first time I have raced on this boat so I wasn't too familiar with the performance but after a couple of boats with slower ratings past us sailing at around 115° true wind angle I suggested putting the asym on the pole to get it out from behind the main and we started sailing faster than them again.

So the answer is for this boat it turns out tacking the asym to the bow sprit is great for up to about 100° true wind angle but any deeper the pole works better. You may ask why not just switch to the symmetrical sail but the asym on this boat is a lighter material and flies better in the lighter winds we had on this race. They are about the same square footage so flying the asym at deeper angles on the pole seems to be the way to go. In heavier wind you don't get so much advantage flying the bigger sails on a reach but down wind the symmetrical spin would be the way to go.