not sure as i don't own a 2" diagonal. I just screwed in the 1.25" adapter and measured distance from edge of adapter to the switch and it was roughly 10mm. It cleared the nuts that hold the switch in place.
http://www.telescopes-astronomy.com....am_philips.htm
http://webcaddy.com.au/astro/adapter.htm
have some more adapters for eyepieces etc