One word of advice from personal experience with LCDs (and modern CRTs as well). Quite a few of them seem to prefer certain resolution/Hsync/Vsync combinations ('standardized stuff VGA, XGA, SVGA and so on), and might dislike oddball Amiga frequencies and resolutions even if they fall within the sync ranges (the software in the monitor itself is 'surprized' by the weird numbers and complains about the frequency being out of range). Standard VGA is 640x480x31 kHz/60 Hz, and IIRC there is also a 640x400x70Hz VGA mode. The same problem goes for some newer CRTs. Whereas my good old 17"CRT would happily display anything I threw at it that was within (and sometimes slightly ousite of) the sync range). Download the manual from the web, and you'll probably see a list of supported screenmodes.
You can perhaps buy it at a place that will allow you to return it within a few days for a full refund? Just in case it doesn't like your A3000.
-Paul
