After making (dutch oven) boules for a while, I've moved to batards, but I find scoring tricky - the cuts open up quite wide right away and then harden, leading to blow-outs along the base of the bread instead.
See the cut on the right for example. The cut on the left worked better.
Too deep cut, too shallow? Too much steam or too little? I know the cuts should be shallower, would that fix it?