Cheers Bruce,

My thoughts are that you are best to use a motor driven telescope type mount, that tracks the sun.  Wider angles lens do better on fixed tripod. You do need higher shutter speeds  for higher zooms, either way, so lower the ISO and use the appropriate aperture. (small apertures show dust on sensor so may need to heal in photoshop later).  You can focus on a distant object automatic focus, tape the lense in fixed focus,  and then switch the focus to manual.

I also suggest using some ND filters to bring the brightness to within the camera range, and even the proper photographic filter has some merit, as you must be aware that it will be very dangerous with large parts of the sun uncovered even at maximum.

Practicing with the sun just above the horizon is good, often in summer the haze has some ND values, and its interesting watching the sun appear to change shape, see my astro site www.astronomy.net.nz for pics I took from an aircraft on 4^th January.

Ironically, my SLR camera is away for repair, so I will have two Canon EF  lenses available to suit EOS backs.. one is 18-55 and the other is 90-300,  if anyone needs one for the event at the Point, I will consider it for sure.

My telescope mount is a bit finicky but I will use my HD video camera on that with the telescopes, and attempt to track the sun, while giving two views,  using solar filters on the front of the telescopes and video.