We (my wife mostly ha ha) have been homeschooling our now 10yo the last 4 years. She is plugged in and has in depth knowledge about a lot of curriculums out there. If you'd like a pretty detailed answer, you're welcome to send over any questions - general or specific at my username @ gmail. I will get it to her and get you something back.
To your OP, following a traditional grade level style is fine, but part of the greatness of homeschooling is diverging from the mainstream and really finding a great match between your kids so they excel. My 10yo likely reads at a 6/7th grade level and just started Algebra this fall. However he may be more in line with traditional 4th grade in other subjects or even behind in some that we haven't been focused on just yet.