I think I did do a few weeks of half speed when starting Preparing, but eventually what I found the most success with was just setting a time for school to take (my goal was to be finished by lunch that year) and we did as much as we had time for, and then finished up any remaining boxes the next day, as well as starting the next days' boxes as time allowed. I hope that makes sense!
The thing I liked about this was that it worked my dd into doing full speed, without her ever feeling like she was doing more work; because we were still taking the same amount of time! She was often able to do all but a couple of the boxes. We would try to save things that didn't necessarily coordinate with the History Box, so our theme wasn't dis-combobulated

. This was also nice because it often saved a light work load for Friday; and it moved us through the Preparing guide slightly quicker.
When we ran Preparing our practice was that everyone did school on a school day. So, if the younger kids had a 5 day week, so did the oldest. We often ended up working around my husband's work schedule with Monday's off and if we did a family fun thing, no one did school that day so it would be a 4 day week. Occasionally (very rarely) we did finish a couple of things up on a Saturday when Dad was at work. This year, I'm trying to be more consistent with 5 day school weeks for my Bigger and LHFHG kiddos, and am really trying to have my dd finish up her CTC work each day. So, I'm rewarding her with a day off if she's working hard enough to get her work done in 4 days. We can use Fridays to bake with Mom, or have a piano lesson (if Mom can get disciplined enough to teach her every week!

) Also free reading time to enjoy a book of her choice. At least, that's the goal.

Hasn't exactly happened yet in 3 weeks.