From the photo, the tool rest looks too long. To prevent hitting your chucks and centers it might be too far away from the blank when you are turning. The tool rest to wood distance translates into one thing - stability. Typically the tool rest should be set so that there is just enough distance to support the base of the tool but not contact the blank. Having the tool rest too close to the work is not as bad as having it too far away. The tell tale sign is vibration and chatter when cutting.
What tools are you using? Traditional high speed steel roughing gouge, skew, etc. or Carbide tools?
Also, what is the main problem you are having? Is it vibration, chatter, catches, etc.?
The rule of thumb for tool rest height is to have it set so that the cutting point of the tool not necessarily the tip, but the cutting edge - for example the side of the curve on a bowl gouge. For traditional tools the height usually needs to be adjusted to accommodate each different tool. For Carbide tools these adjustments may be less frequent as most Carbide tools are designed to be used like scrapers with the tool presented level and the scraping edge of the cutter on the centerline of the wood.
Regards,
Dave