hi Ian
I don't have one of these brushes myself, so I'll speak in general terms.
Firstly, the recommendation from Dry Fusion UK is not to use them on low profile tiles as the benefit is minimal. Stick to pads.
As for the machine pulling to the right. I use a normal rotary machine with a dense polypropylene scrubbing brush. There can be more drag and torque reaction compared with a pad. I suspect it may be a case of refining your technique. After start up, relax your grip a little on the handles. Gently push the handle down to move the machine to the left to find the optimum balance point, or lift the handle up to move to the right. These should also be the only movements you require to move your machine left or right. Try adjusting the handle height as the brush may be thicker than a combined drive plate and pad, so the machine is now higher. On Flotex type carpet, any rotary brush machine will be a vicious beast. Other low profiles less so to varying degrees.
Safe and happy Fusioneering:)
Ken