momof3kids,
Thanks so much for coming back to share a bit more about your son!

That really helps us so much! I agree that having your son's current teacher give you a list of sounds that your son has covered is a great idea. I'm thinking that your son needs to finish out his phonics instruction, so to do that I'd lean toward using The Reading Lesson (and either starting near the middle of the book, or starting at the beginning and moving quickly through what he already knows).

After that he will be ready to go through the Emerging Reader's Set.
I'm going to link another thread of yours running on the board right now, just to help all of us have all of the information needed to help place your son well. Link:
viewtopic.php?f=6&t=13628
As far as placement goes, it does sound like your son could handle Beyond. However, if you end up slowing it down too much you may quickly find that doing LHFHG at full-speed would be a fuller program then Beyond at half-speed (for a long period of time).
If your son can handle Beyond, then I wouldn't drop below 4 days a week at full-speed. Otherwise, he would be better placed in LHFHG at full-speed if he cannot handle Beyond at full-speed.

If you do need to slow Bigger down for a season when you get there, then that is fine. However to slow Bigger down over two full years would really slow down the skill progression in Bigger so much that your child won't be ready to handle the rigor of Preparing when he gets there. For this reason, it is best to go full-speed for the majority of a guide in order to prepare a child well for the next guide in line.
Usually when we speak to families who feel that Preparing was too much for their child, we discover that either they have placed their child too high, or they haven't done everything within Bigger that will prepare their child for Preparing (meaning they weren't consistent with teaching all of the boxes in Bigger). If you do the program as written, you will truly find your child well-prepared for the next guide in line.
If you are concerned that Beyond will be too much, I'd lean toward LHFHG instead. If you feel that Beyond would fit well, then I would plan on a full-speed 4 day a week plan at the minimum. With this being your first child, you will have the time needed to work with him and get him going. Slowing down is only needed if the momma's schedule is too full with many others to teach, or if the teaching within a previous guide was sporadic, or if the child just needs a bit of growing room at the beginning of the guide. Otherwise, heading forward as written is the better plan!
Blessings,
Carrie