bman,
I don' know what your local codes call for but some require railings that end in a newel post or return to a wall. There is also some gobblety gook about the width and thickness in the way it can be grasped. You might want to check on all this before you put to much thought or work into it. The dovetail design may not work if they require termination at a newel post or return to wall. (As I understand this is basically to provide something for someone to grab if they are falling as they enter/exit the stairs and is supposed to prevent people or children from sliding down the rail) There also may be code for distance/space between pickets/balusters. I think it is max of 4" here. Supposed to prevent children from sliding through or getting their heads stuck in between.
Here is a design for balusters I saw done for an outside balcony on a local job. It looks real nice completed and is very simple. If you use copper water pipe for balusters it can be left to age with natural patina and metal artwork can be done from sheetcopper and soldered to balusters. This is a little pricey. Using black steel gas pipe will allow you to use rolled steel for artwork weld it in and do it a little cheaper.
The basic idea is a through mortice and tenon pegged in place for the rail/post connection. It is extremely strong done this way and you need not worry about shrinkage. I doubt that the through mortice would take any longer to cut than the dovetail joint. Holes drilled in the bottom of the rail to receive the pipe are also very easy and time effective.
For continuous rail interrupted by posts the second figure shows a passthru half lap splice.
Nothing is more irritating to me than wobbly railings/posts. The dovetail joint would do little to prevent post movement. This joint provides a "continous" horizontal member to help brace the post.
Fig 1.
Hope this sparks some ideas or others thoughts and good luck.
Fig 2.
