Hey Adam – thanx for your note and congrats on your worlds slot!
The case-by-case approach is generally the best way to string together a long-term preparation. In your situation, it would be best to do a focus block on whatever weakness you have, between the swim stimulus and 16-week plan.
As a tip, your weakness, might not always be a particular leg of the sport, but could also be general endurance, or handling higher intensities.
All the best!