I don't suffer the fiberglass "allergy" that some do, but I do get some minor irritation. I've put off the project till now as I wanted it to be cooler, say 35-45 degrees so that wearing coveralls, respirator, hat, gloves, etc is more comfortable. But the weather has been fantastic, so T-shirt, respirator, and jeans it is. Personally I prefer to do the tear down outside as it saves the shop from billowing clouds of dust, could try a dust collector like Joe did, but don't own one. Thought about making one either from a furnace fan or shop vac, but then that's time away from the actual work. The task actually took longer to clean up the torn out stuff than to actually perform the tear out.
BTW, I suspect the top of the Timi weighs maybe 250lbs minus the engine cover, which is maybe 20-25lbs? I used a four post lift, but the task could be easily handled by four people at the corners. The top is now resting on another boat trailer with a bunch of 2x4's screwed together to support the top in 6 places.