No reason you couldn't install a topping lift, I've often thought about adding one to my DS II. However, I might still use the boom crutch myself even with the topping lift, to keep the boom centered while moored and stop it from swinging as the boat rolls In waves. I keep the mainsheet tight when not sailing, but the mid-boom mainsheet still lets the boom move a bit side-to-side. If I had the older, "Crosby-Style" mainsheet that formed a triangle across the stern I might be able to go without the crutch. A topping lift would sure be nice when I'm alone, it would allow me the lower the sail without letting the boom drop to the deck. If you were to use a boom tent over the cockpit you would really still need to use the boom crutch to support the boom while using the boom tent, otherwise the topping lift would need to be VERY tight and still might allow the cover to sag.