I've gotten such great responses from you all, and I am so grateful for the tremendous amount of help I've received! I don't have time at the moment to reply to each response separately, but I've read every word and soaked it all in. Thank you all so much for all your help, truly!
I was very close to making a decision on which levels to use for my kids, but before I ordered, I thought I'd try calling HOD, just for some extra peace of mind. I left a message, and received a call back from Julie, who was so incredibly sweet, kind, and patient with me, and we discussed each of my kids' academic levels, abilities, and struggles. We talked for just over an hour (it didn't even feel that long, as she was SO friendly and easy to talk to, that I felt like I was speaking with a close friend!) and at the end of the call, I had such a beautiful peace in my heart about where to place each of my kids. We even came up with a tentative plan for my littlest ones as well, for when the time comes. Without a doubt, HOD is most definitely the right place for my family as we begin our homeschooling journey, and I am SO grateful that God has led us here! I honestly cannot say enough what a wonderful impression I've received of this company so far, along with the helpful and kind community I've found on these message boards as well. I am so happy to be here, and thrilled and excited to begin homeschooling with HOD this year!
So, what did I end up choosing for my kiddos?
Well, for those of you who suggested LHFHG for DS2 and Bigger for DS1 - which was most if not all of you, LOL - you were spot on! After reading all of your replies and digging deeper into the placement charts, the scope and sequence of each level, and reviewing the sample pdf files, I started to come around to the idea that Bigger might be the best placement for DS1. After talking to Julie, and learning more about this level in greater detail, we were both convinced that Bigger should suit him just fine. So, I went ahead and placed my order last night for Bigger, LHFHG, and LHTH (for DD1, who's 3). I was so excited to press that 'submit' button, and have this decision behind me, LOL!
I feel very good about my choice, and I will ease my son into this level and take it at his pace. I am pretty confident that he will do well!
Side note, I'm also SUPER impressed that, even though I placed my order last night at around 9:30 pm EST, I already received a shipping notification email this morning, around noon. Wow! My package is scheduled to arrive by Monday, so only a few short days and our goodies will be here! I'm very, very excited (in case you couldn't tell, LOL).
Thanks again for ALL of your helpful replies! I appreciate it very much!