I love the size of this bowl, I use it for everything. I just wish that since they copied the 1950s version of the C3 Mixer Combi-Whip, they would have also copied the old method of 6 spot welds on the brackets instead of 4.  The dough hooks from the K45 do fit, just make sure you have a soft, hydrated dough, so it doesn't strain the weak welds. I make half loaf bread dough twice-weekly in it, which is less of a strain than cookie dough. Perfect size, maybe you will make one dedicated for the 5 quart pro, so you won't have to have two holes on one bracket and therefore less torque?  Just saying.