If it is walking my money says the engine is too low, I have a 21 CX with a 300R, it will run 81 plus, you do have to drive it but it will run 70 without having to touch the wheel.
9 times out of 10 this is the case, SEAT TIME will fix it though in time.
How do you solve the blowout problem on launch it you don't have the motor in the water? Take off low and raise it up? I have a bobs hyd plate. What height setting for running are you guys using?
Really can't compare a cx19 with 225 and cx21 with a 300. They are several posts in the Facebook groups about chine walk with the cx19 and what people have done to try and correct it. Some successful, some not.
I suppose it could have something to do with how the boat is loaded, I know I can drop my engine down lower than normal and get my boat to walk big time at WOT.