We are doing Bigger and Little Hearts as 4 day a week programs although we are going half speed with Bigger. I also did Beyond as a 4-day last year. Some people prefer to just do 4 days, then start the next week with day 5, etc. I like to get the whole week done and just have the wiggle room you are also looking for
I have a weekly chart where I fill out what we are going to do each day. I watch for "lighter" days in various subjects and just add in an extra days work there. For instance I do the narration and 2 days of history reading on day 1. Because Bigger is laid out the same each week this makes it pretty easy to find a schedule that works. We still do math and grammar on day 5 because I feel like it's too much for me to add in an extra day, BUT my daughter will often ask to do the extra work on Thursday so she has less to do on Friday and I'm fine with that! I also save the art projects for Friday. I feel like I'm less rushed that way and it's something fun to look forward to on Friday. Assuming we get through everything I have a few things scheduled just for fun like a cooking lesson, learning a few new words in another language, etc.
It worked REALLY well for us last year and so far it's been good this year as well. We're only on unit 3, but we've been doing lessons for 6 weeks.
Melissa (Pastor's wife in NC)http://gracefilledhomeschooling.blogspot.com
Rose (7-years-old) - Bigger Hearts, piano, voice
Beth (5-years-old) - Little Hearts for His Glory piano, voice
Grace (3-years-old) - Little Hands to Heaven