Re: tacking angle
As stated by others, the answer to the original question really depends on the boat, the sea state, etc. Typically in light air you wouldn't be TRYING to point as high as possible, at least not until you have built up some boatspeed.
The boat's keel design is a large determining factor. My current boat has a pretty conventional deep fin keel with a pretty big chord length, (the fore-aft measurement) which makes it very forgiving. It will start to develop enough lift to start to point at relatively low speeds. In higher wind ranges it points very high. My last boat, on the other hand, was a high performance racer with a very deep narrow chord fin with a bulb. That keel required much higher speeds in order to start generating lift. In lighter winds I could not even think about pointing with other boats in the fleet until I got moving.
As for shoal draft keels, there is just no way a shoal draft boat will be able to point as high as a deep draft keel. Two identical boats, one with shoal one with deep, and the deep draft boat would KILL the shoal up wind every time. The shoal draft just doesn't have the surface area to generate the lift.