What you are doing walk wise is about right for their age, though I would be inclined to take them fo 3 10 minutes as opposed to 1x 10min and 1x 20 min. Nothing is set in stone regarding toilet training, my youngest GSD was 6 months old before she was completely clean, through the night as well, my other 3 dogs were a little earlier, your pups still need to be taken outside after eating/drinking/sleeping/playing etc as I expect you already know, and of course last thing at night, you may have one get clean before the other.
You are very brave getting 2 puppies together especially Springers, I remember my sisters Springer when he was a puppy!! My breed German Shepherds are generally quite laid back, though they do go through a very 'testing' stage, I usually get to this stage and say "Never again"........until the next time of course, lol.
Have fun.