How much buffer should I give myself when setting the Scale Minimum and Scale Maximum ranges? For example, my imaging setup's FOV (per Astrotortilla) is 20.62(X)27.73 arcmins. What do you recommend I put as the Min and Max?
It looks like you're imaging close to 2500mm. I get 18.82' x 28.27' arcmins with my 10" LX200GPS and DSLR combination. Try my setting below. I typically go 5-10 above the maximum and below the minimum. As long as your setup doesn't change, the FOV should always remain roughly the same. I don't know how your screen captures affect the final size if you are cropping the image or adding extra border information. The scale is 100% accurate only with your actual image file from the camera.
Lastly, how do I turn off the Config setting which automatically determines the range search of the next plate solve I will do? It seems to store the range of the previous successful plate solve, and then automatically begins with this range for the next plate solve I try to do. I would like to turn this feature off so that I can just set a permanent range for it to search within (e.g. the FOV of my current imaging setup +/- some buffer).
You must be talking about the Default setting. You are able to load, modify and save new settings from the file menu. The default configuration file [astrotortilla.cfg] is located in your local user folder under Windows 7. It may be somewhere else with another operating system.
You can either overwrite this file or create a new file which you will have to load each time you what to solve at setting other than the default. I've created six different setting for my various setups.
You will need to experiment with the SIGMA value to get the shortest amount of solve time. It all depends on the level of noise in your image.