1/2 IM training plan

I was very interested in the thread discussion 1/2 IM speed as a function of speedwork vs endurance work. I made me really reassess my training plan for the coming year, and I need opinions on my training plan (macro perspective). As a point of reference, this is my 3rd year of tri. 1st year I did a couple of sprints and oly’s. Last year I did WF 1/2 in 6:15, and Vineman in 13:29. Clearly, from the previous thread my limiter is endurance. I’m using Joe Friel’s “Triathete’s Training Bible” to build my plan for the coming year, and before I read the other thread it looked something like this:

Base 1- 4 weeks
Base 2- 4 weeks
Base 3- 8 weeks
Build 1- 4 weeks
Build 2- 8 weeks

This is leading up to my first “A” race of the year- Wildflower LC 2004. In addition, I’m planning to incorporate Gordo’s IM strength training plan, his stretchcords workout for swim strength, and his core strengthening workout. My question is- is the above training plan too focused on speed (12 weeks of Build phase)? Should I be doing any “Build” phase if my limiter is endurance, or should I just be focusing on the three basic limiters- endurance, strength, and form and forget about speedwork? If so, what would that look like? Base 1 x4, Base 2 x4, Base 3 x20 weeks?

the same question, you can probably find his response by searching their forum. Basically his response was that for the 1/2 IM distance the Base and Build are very similar. He still recommends going through build because very few people can keep up the load encountered in base training for an entire season.

Using the VC from training bible, my only bike speed work during build is 1x60’ entirely in zone 3. The only speed work I do running are long zone 3 tempo intervals.