To help clean my bowl after making a sticky dough, I fill the bowl with water up to the top of the blades, add a dash of detergent, then heat 3 minutes / 60 degrees / speed 6, remove the bowl from the carousel and allow the water to sit in it for about 30 minutes, empty the bowl and most of the dough will have melted into the water and there should be very little left to clean. A quick rinse through with a Thermomix brush will do the rest - if there is any dough left.
This is actually quite a quick recipe to make as most of the time is taken with waiting for the dough to rise on two occasions (roughly 45 minutes the first time, and 45 minutes to an hour the second time). So I have noted in the recipe link that total time from start to finish is approximately 3 hours including baking time (2 hours 30 minutes prep time, and 30 minutes baking time), but this will largely depend on room temperature on the day.
If you wish to make this in advance, and I have done that often, then once the bun is cool, double wrap in Glad Wrap and place into the freezer. The day before you plan to serve it, remove bun from the freezer the night before and leave on your kitchen bench overnight to defrost. Thirty minutes before serving, place cinnamon bun onto a baking tray, spray with a little water, cover top with Alfoil tucking a couple of the Alfoil edges under the bun to keep it in place, and refresh in a preheated 180 degree fan forced oven for 15 to 20 minutes (I usually do it for 20 minutes but this will depend on your oven). Serve whole and allow guests to pull off their own pieces.