
Welcome Ginger!!
This is my 1st year to use Bigger and DITHOR and it works great! Like water2wine said, DITHOR is the reading program reccommended to use with HOD. If you don't use DITHOR, you'd need to be covering that using some other program, so I wouldn't say that it "adds" any time to your day. DITHOR takes us about 20-30 minutes to do. We're really enjoying it.
I'm going to type one more thing that I was a little confused about when I was first looking at Bigger and DITHOR...feel free to ignore it if it all makes sense to you, but from your post, I thought you might be confused about the same thing.

In the daily plans there is "storytime" scheduled as well as "reading choices". Storytime is where you will read to your child. Reading choices (DITHOR would be your reading choice) is where your child reads to you. In the Bigger manual these both use books from the 9 literary genres. You don't have to worry about trying to stay in the same genre for both.
Some moms use DITHOR 3 times a week rather than daily. That's up to you. I'm using it daily this year, but I know that when we get into Preparing it is scheduled to use 3 times a week.
Feel free to ask any more questions. The moms here are very helpful!

Kathleen