Depends on whether you get the 52mm or 60mm pillar gauge holders, but most gauges you can get in either size.
If you get the dual pillar gauge holder, be careful about visibility, and how far they stick out. Pillar gauges cannot stick out more than the steering wheel, and must not block drivers side front quarter panel visibility. They (at the pits) are very strick on it. I have a permit for my dual pillar gauges, and the guys at the east perth pits, were going to try and revoke it and they refused to give me my permit back and made me go and see the technical team at welshpool pits. Luckily, because I have a permit that said 'pillar gauges' not 'pillar gauge', they couldn't do anything, although they weren't happy with it. They took a photo of it for records. My top gauge does stick out further than the steering wheel, and blocks some of the view. Trying to get a permit for them like that now would be almost impossible.
Cheers
JB