I think that recipe could be good, but you might want to have a bigger hop addition at the end. 0.5oz isn't all that much, but it depends on how intense you want to have the hop character. For me, I would probably be more like 1 or 1.5 oz of each for the last addition or maybe put more at the dry hop stage. I haven't used Calypso, so I can't speak to that.
On the grain bill, I think you could leave out the rice hulls. At 10% of the grist, you won't have problems with it getting stuck. I regularly use 10% oats (or more) and never use rice hulls. I do tend to have the mash on the thinner side (higher water to grain ratio) which maybe helps that.