If you haven't already read Glenn Doman's "How to Teach Your Baby Math" book, this is the great resource. My understanding is that LM is based on Doman's program. As such, I'd start with quantity recognition and not introduce equations until you have passed at least 20 in quantity recognition lessons (number 20 that is, not lesson 20). Doman also doesn't recommend introduction numerals before quantity recognition is established and before you're done with equations.
Yes, LM lessons are short, and I haven't seen multisensory content yet. Doman generally recommends short sessions, but there are a lot more of them through the day, so if you think that it's not enough, you can show the same lesson up to 5 times a day.
Hope it helps