There are probably more people that have gone into that particular program and run horribly than ones that have done well. It tends to work well for taking people that naturally have a lot of speed or are just plain good at the 100/200 and turning them into good 400m runner. People that lack speed tend to have minimal progress.
If you add in speed every other day to the Hart program, then it isn’t the Hart program. His program is built on lots and lots of tempo (extensive and intensive). They do some speed makers and starts…. but that won’t be enough for a lot of people.
Who knows though… you seem to really want to do his program, so try it out. You might do extremely well with it. You also said before you only wanted to run around 80% or so, so worst case scenario you at least enjoy yourself more in training.
Yes, I am really intent on trying at least some version of Hart’s program. I agree that it may not allow me to develop speed, but I hope that the changes I will make to it can make up for that. Thanks for the input though.