Preventing baguette "explosions"

Good morning -

I've been on a sourdough baking streak for a few years now and am being tasked by a kink I still need to work out: baguette explosions (evident on the topmost baguette, and a bit on the lowermost one in the photo below). I'm hoping the more experienced bakers in this forum might steer me in the right direction here. A few observations:

- Though I'm now using perforated pans because of the wonderful bottom crust they impart, I recall not having this "explosion" issue when I baked my baguettes on parchment paper on a stone.

- As you can see by the resulting "hats" on the boules, my oven does not produce even heat.

Thinking about the factors most likely to contribute to the explosion problem, I tend to think it's shaping or scoring...but then there's the resolution of the problem when I use parchment/stone...so is it really shaping and scoring? I've considered going back to the stone, but given I like to produce a variety of shapes in one bake, the perforated pans -- and the baguette pans, which prevent the baguettes from "spreading out" laterally -- give me more surface area in which to do that. And about the scoring -- could I be scoring too deeply?...too shallowly? 

Any ideas most welcome!