How's your support system, do you have family in the area? Are you in a suburban setting or rural area? You don't mention what their ages are. Where do you do the lessons; is there a defined space in the house where ,say all the educational things are stored and set-up? How do the boys approach lesson time, do they have a schedule that they recognise or say a special time that they know is school time. I see where you say you must keep the time frame flexible in order to maintain attention but is there an arranged system you follow; like a structured procedure for beginning and such? How do you manage to seperate them in as far as their capabilities are so different? Can I ask what State you live in? I'm not a believer but it is my expressed beliefe that what works for you is the right thing.