Hi Richard,Useful but is anyone doing it
Some builders would not consider this important, others do, but it is your model, so go with what you want. The keel is tapered forward and aft with the dimensions you show above. Keep in mind that if you ignore the actual dimensions of the keel but the knee of the head is properly tapered it will not match up with the boxing joint, and if you taper the stern post properly but not the keel, there will be a shelf on top of the keel at the post.
Your model, your call.
Allan