Artrage 6 - color sampler options

[Dennisaa]

Hi
(First post - be gentle)
I've just upgraded to Artrage 6 from 4.5, and the color sampler tool gives me choices I did not have before (or perhaps just a different interface)... and questions about how to use those choices.
These are the options:

• Large area
• Only Brightness
• Only Hue
• Only Saturation

I'll focus on Large area as the most interesting and useful to me.
Frustratingly I can't change the size of the sample area. Please see the photo - it evidently takes some meaningless average of a fixed area.
I need to have control over the area it is sampling.
Grateful for any advice on this enhancement - any search in posts or google pulled up old V4 articles. I found no references to the enhanced features. (maybe I didn't look hard enough)
Thanks a lot.