Hello…

I have done several of this, some as long as 10-15 minutes – I found Flash for none web based presentation to be too convoluted – We normally used sWish (sWishZone) – As far as resolution it’s all relevant to the type of connection between the screen and PC

*If you are using VGA (D-15) then
The ideal resolution is the screen native or MAX in this connection platform not necessarily the screen max resolution in HDMI or Component Video

*If your video Card has Component or HDMI output I would consider 1366 by 768 or 1920 by 1080... (If the screen can go there!)