I think the rear panniers and handlebar bag can work perfectly well for you. Get your gear together, spend some time figuring out where everything goes for convenience and weight distribution and then try a couple of weekend trips to work out the bugs. You'll get use to how the bike handles quickly enough. Don't let debating the nuances of weight distribution get in the way of actually touring...millions of miles have been ridden with every combination of bags and 2x rear panniers and a handlebar bag has worked perfectly well fo a lot of people and will work for you.

I keep my valuables, daily food, electronics and rain gear in my handlebar bag and always take it with me whenever I leave my bike. That way if my bike is ever stolen I still have everything I need to recover. I use a saddlebag and handlebar bag set up and keep weight down to make train/bus/air travel easier and to make my life on the road and camping as simple as possible. I usually use a big (23L) Carradice Camper saddlebag, but recently tried out a Caradice Nelson Lowsaddle Longflap and it works ok, but I had to move my cooking stuff to the handlebar bag to get stuff to fit...and my tent poles had to be carried under the Longflap rather than inside the bag.