Tamiya tape can be made more conformable by cutting it thinner than it already is & Vinyl pinstriping tape from the likes of 3M is even more conformable.............
I'm not sure if the de-icing boot is scribed onto the tail of your kit, but if it's not you could use some sort of Heath Robinson trammel / marking guage to mark it out lightly - this would give you something to mask against, as I imagine it would be hard to get it correct without some sort of guide.