Advice for next year calendar season

Trying to plan next year season
I am heading up for my first full Ironman on Sept 11. (Madison)
Planning to do one or two 70.3 in June
Question is should I just do training plan for 140.6 ( all three ( base/build/special) from the beginning or do a complete training ( base/build/ specialty) for 70.3 and then a short version and the do ( build /specialty ) for 140.6 in the months between June and sept ?

Thanks very much for the advice

More Base is always beneficial so, if you have time, why not go Full Distance Base, 70.3 Build/Speciality then Full Distance Build/Speciality for a second peak (if you can stay focused for that long).

Or give the plan builder a try…