"it's physically larger than the C head, and now the cutting head drifts down to the bottom of the machine, where it lurks, waiting for my shins (workshop layout is tight!)"
Update to this.
Just finished a large fiddly DiBond mounting job. Prior to starting, I called Keencut, to see if there is anything I can do to fine tune the counterbalance on the steeltrak. Instructions were emailed to me moments later, but didn't provide enough resistance to support the cutter head.
Their plan B: they sent out a replacement C2 cutting head, which has just the right amount of material cut out from it to make it weigh the same as the original cutter.
I've said it before, Keencut's after sales service is every bit as good as their products, which are first class.
I reckon the roll is a couple of mm at most.
With the new cutter head, I was able to cut and use strips 76mm wide on the LHS, something that I couldn't have done on the previous model.
Oh, and their new 080 blades are seriously awesome. Clean, low resistance, wickedly sharp and hold their edge