When i get an angle like that Sheld', i tape it as per normal, then round it over, if you know what i mean. If you have a gauging trowel,,, then using the end of it, make the angle rounded.
Method:
Put some bonding plaster into the 45 degree angle, then run the shaped end of the gauger, (edgeways), along the sharp angle,,, so you've made the 45 deg. angle right at the top,,, rounded. Let the bonding set up, then "brush" on some multi finish, and smooth the "round angle" off with a piece of polythene, wrapped around the 1" or a 1.5" paint brush. Take your time smoothing it off, as it sets. I do them that way all the time. It looks great when finished!!