Beyond is a great guide, but so is Bigger!

You will get to do Beyond with your younger dc eventually. I think your 2 older dc sound accurately placed in Bigger Hearts. Your almost 9 yo's work in Bigger Hearts sounds typical for beginning the guide.

I think she is doing just fine! The work within Bigger Hearts will not get harder, and your dd will continue to grow and mature as she moves through the guide. In Bigger Hearts, I try to have my dc able to do the maximum amount of work in the guide by the end of the year. So, for example, by the end of the year, I try to have my dc doing 3 vocabulary cards, all of the poetry copywork, the most work that is suggested in notebooking, doing all of the writing themselves, etc. This has worked incredibly well, and always ensures they will transition into the next guide smoothly! So, I would start having your dd write one line of poetry copywork a day to begin with. Then eventually move her to 2 lines a day, etc., until by the close of the year she is able to copy the entire poem. I'd keep going with 1 vocabulary card awhile, but maybe a third into the year, have her start doing 2 cards, and maybe just the last month or so, 3 cards. She is going to do just fine! The start of the guide is always "training time". Just remember, the intent is to have about a third of it be work dc are familiar with, another third of it should be skills they somewhat know but need to practice, and still another third should be brand new skills that by the end of the year dc will be ready to move into the "practice more" mode the following year in the next guide. If absolutely everything is a piece of cake in the guide from Day 1, a child is probably not placed correctly. HTH - but just keep on keeping on - rest assured your dc are doing just what they should within Bigger Hearts, and they will continue to grow and mature more and more with what they can accomplish throughout the year!!!
In Christ,
Julie