72dpi is perfect for Websites. maybe you could use 90dpi here for some more modern Monitors. in General 72dpi fits perfect. 1000 x 2000 Pixel... the pano sizes in general are horizontal x vertical measured... so you have a pano with 2000x1000 Pixel. and because of Ration of 2:1 I asume ist a full sphere pano covering 360"x180".
is the Pixel Count big enough? it depends how deep you let your users zoom into the Image. so if you let them zoom only 60% to the native size its ok.... I would say.
but in general I would say using a fishey lens and a modern/moderate modern DSLR cam you get 6-8 Image pano with Minimum 3900x2600 Pixel per single Image (EOS400D with 10mp) with a modern 18mp cam a pano with 20.000x10.000 Pixels should be real no Problem and because of panotours ability to create different zoomlevels the enduser never Need to load the complete pano at once - only the part visible on Screen and only the according tiles of the zoom Level selected by browsing the pano.