Welcome to the forum!
Little Reader should be great for both of your kids. They will see and hear the words plus see pictures and hear other sounds associated with the words. A LR lesson is just a few minutes long, depending on how fast you flash the words. I'd say no longer than 10 minutes. LM is much shorter.
I am on my way out the door, so I can't post more, but why don't you download the free trials and try them out?
Thanks for your response, it does make sense........ I think I am going to give it a try and thanks for the welcome Zaku