Help finding the right plan

Depends on your current fitness. 16 weeks to a HIM is a relatively short time coming from a lower fitness level.

The Olympic to Half Ironman Bridge plan has these minimum requirements for athletes

1. They have a very strong base of 4-6 months of consistent training

2. They have a strong swim or run background

3. They have trained for at least 10-12 hours per week

The Half Ironman - 20 Week plan has these:

1. They have a very strong base of 4-6 months of consistent training.

2. They are well balanced in all three disciplines.

3. They have trained for at least 8-10 hours per week.

 If your current volume is around 8-10 hours per week, I'd go with the Half Ironman - 20 Week plan and start at week 5, cutting out some of the workouts. That's actually the biggest volume week in the plan.

This is from the coach who wrote the program:

On the first question, the plan was for athletes that already have a strong base and are balanced in all 3 disciplines. Because of this I wanted to get the volume up early, then add the speed stuff in. For those athletes that want to get faster at the 1/2, they need to focus on doing tempo and LT work, not just base. So, with the idea that the athlete had already done a good amount of base, I incorporated more race type efforts, which mean less volume.
 
The periodization is pretty basic in that there is a 2 week build, 1 week rest pattern. The 1st 5 weeks are more volume based, then we get into that LT/Tempo work. The only deviation is in the middle where I wanted to give the athlete a bit of break, so there is a rest week (#9), 1 hard week (#10), then a rest week (#11). I was worried about burnout, both mentally and physically. After that it goes back to the 2 week build, 1 week rest until the taper at week 16. That gives the athlete a total of 7 weeks of hard work w/ rest weeks interspersed.