I carry a backback of the size to hold a laptop. Basically, can you comfortably hold it in your lap for the 15 minute flight? That is pretty much where it will have to be. So by the sounds of it, yours should be fine as a carry on. On the bags, 44# is the limit per person, but the key is the aggregate. If you have someone else with you, you get 88 together. It can I hear get expensive for overages, but I have not experienced it.
