Justin,
I bought this same scanner a month or so ago. I used it to scan the Preacher 9.8 that you bought from me. I'm not at home at the moment to look at my settings, but I use Paint to scan the comics. You make a custom settings for DPI, Contrast and Brightness. Someone did post their settings in this thread, and I used those.
When I open Paint, I click on the menu, select "from scanner or camera", select the 8250, click custom setting, make the adjustments, then select "scan" (not preview). With the scanned slab now in paint, I crop it and save it in JPEG. It will default to PNG, but I find these files to be larger and thus longer to upload to photobucket and the registry.
Hope this helps.