Roger
It wouldn't matter. The way I use the tool is pulling up, pulling down, working my way down the first tube (it's really a channel), then repeat for the other six To do this efficiently, you have to retain your grip on both ends of the chain, and pull alternately up and down. Since both arms are reaching in, one in the top plenum above the hx, and one in the reaction chamber below, in order to pull vertically, more chain doesn't help. Guess I'd have to show you. If you're short, or just short in the arms, you're left with pulling the tool down until it sticks, standing up, pulling it up until it's free, leaning down and pulling it down until it sticks, etc. etc. etc. Very slow, and hard on the back.
It's a design limitation, and as far as I'm concerned unsolvable for me. The best solution is to avoid enough buildup to jam the tool, which means weekly cleanouts. Go to two weeks with average wood, and you're likely going to be cursing a blue streak.
The crappy links they use for the chain connection to the actual H-bar cleanout part need replacing, also, as it's too easy to pull them apart, leaving you with the tool stuck in the channel. For what we pay for these units, THAT's unforgivable.
Yep, we hit -32C (about -26F) last night. A half-full firebox lasted 9 hours, but it's not the best wood, only 20% oak/ash, 80% poplar and birch; none of it is as dry as I'd like.