I did the same 0 to 1650 workout yesterday and today that I did Thursday. I even read the manual for my lap counter and used it! I won't be posting all my swim lap numbers on the blog, but I average right at 1 min per 50 yard lap. Using this data I estimate that I should be able to complete the 1.2 mile swim in about 45 minutes, which is about a typical half Ironman time. So that's good.
I'm really enjoying this swim training program.